As I have said elsewhere, my favorite painting surface for acrylics is watercolor paper.  For plein air work I now prefer to bond a piece of 140 lb cold press watercolor paper to a 9 x 12-inch piece of 1/8-inch MDF board using gesso.  This works great for acrylics here in the northwest, but it remains to be seen if I will be successful this winter in the dry climate of Arizona.  Though I haven't used them yet, the Golden Open acrylics (long open time) may prove to be my salvation for using acrylics en plein air in Arizona. I also plan to try bonding a piece of canvas paper to 1/8 inch MDF and use with Open acrylics in Arizona - stay tuned.

One of the properties of acrylic paints is their ability to stick to nearly any surface that is free of grease, oil or wax.  I've painted on a variety of surfaces with acrylics including regular cotton canvas, fine mesh cotton canvas, canvas board, smooth MDF board, mat board (all primed with acrylic gesso) and watercolor paper. I find that time and time again my best results happen using unprimed cold pressed watercolor paper.  Watercolor paper provides both a small amount of "tooth" on the surface as well as some absorbancy that is not offered by any gesso primed surface. This allows me to do very thin gradational wet on wet washes as well as having intense vibrant thick colors produced using a painting knife. I also can mix watercolor and acrylic paint on the same surface so long as the first layer is watercolor.  Since I do  a lot of painting of water scenes I find that I can get the illusion of wet surfaces far more easily by painting wet on damp using watercolor paper. I've tried using absorbant ground on my gesso primed surfaces, but the resulting surface still provides insufficient absorbancy. Acrylic placed onto a gresso primed surface has to be put on thick in order for the color to "stay put" on a brush stroke. The underlying surface is just too slick.  This results in very amateurist looking blocks of solid color unless one works very rapidly to blend in differing colors before the paint sets up. Generally I prefer to make many thin layers as opposed to a single very thick layer. I suppose this comes from my background as having first been a watercolorist.

When plein air painting I prefer to use gesso primed surfaces, either mat board or MDF. In this case I need to work very fast to keep ahead of the changing lighting conditions. I don't have time to wait for multiple layers to dry. Instead, I make a quick underpainting of the major value blocks then apply very thick paint and blend colors on the panel as I go, more like an oil painting approach.  I should add that acrylics work only as long as the air temperature is low and I'm not working in direct sun, especially in the Southwest. 

I prefer to paint on a totally flat surface for both watercolor and acrylics, and my preferred surface is 140 lb watercolor paper.  Usually stretching will provide fairly flat paper but doing large areas with wet on wet will still cause some ripples on 140 lb paper.  Although 300 lb paper eliminates this problem it is very expensive.  One way around this is to bond a sheet of 140 lb paper to a piece of mat board using rubber cement.  Like most painters I have lots of scrap mat board as center cutouts so the only additional cost is for rubber cement.  Coat both sheets with rubber cement, assemble while still wet then weight it evenly for several hours to get a tight even bond.  Then, voila, you have 300 lb sheet for very little cost.

You must be careful to get an even bond across the paper,  otherwise large local bumps will form when the paper becomes wet.

For an easy to use palette for acrylics, especially for plein air painting, use a piece of window glass taped to a white matboard backing.  I use a piece of glass 8 x 10 inches  and spring clip it to my French easel. The white backing allows me to see the true colors of each mix.  Just let the acrylic dry on the glass then scrape off with a razor blade for easy cleanup.  This tip is based upon usage by Rodger Bansemer.

The five most important elements in painting or drawing regardless of medium are: shape, value, value gradations, placement and edges. 

Our visual perception of three dimensional objects on the picture plane is controlled by the shapes and placement of various blocks each having differing color values from those adjacent to it. Whether we perceive the shapes as being flat or curved depends upon the gradations in value within a given shape and the nature of its boundaries with adjacent shapes. An abrupt edge signals a sharp break between two blocks whereas a gradational edge signals a curved boundary.  Another element is texture which is really a type of value gradation that is repeated in some way.  By proper manipulation of these elements masterpieces have been created without any concern for color.  Making use of the additional color properties of hue, intensity and value certainly adds to the interest of most paintings and provide still more challenges for the artist.

Pencil drawings are particularly useful for new painters as they provide some simplification of subjects in that they only have to worry about  shape, value, value gradations, placement and edges.  Drawing is really just monochrome painting in shades of gray, so extensive drawing practice makes for better painters.  I will repeat what has been told by many good artists - If you want to paint well then DRAW, DRAW, DRAW.

For my approach to watercolor I need absolutely flat paper, ripples from expanding wet paper are not acceptable.   When wet, watercolor paper expands mostly in one direction (about 3/4 inch in 36 inches) so if it has not been prestreched you get ripples as soon as your watercolor dampens the surface.  These really create havoc with obtaining nice smooth graded washes.  The secret to making a good stretched paper is to use a somewhat flexible substrate like 1/4-inch thick masonite.  Wet the WC paper thoroughly for about 5 to 10 minutes then lay it on the masonite.  Let it set for a few minutes while more ripples appear then pull them out and follow with gummed tape and stapling every 2 inches on the edges.  the tension developed as the paper dries will bow the masonite somewhat so that the dry paper becomes like a drum - taught and smooth.  When the paper is again wetted by the watercolor the bow in the board will flatten somewhat but still some tension will be retained on the paper - no ripples form though.  The key is that the board must be somewhat flexible so the spring of the material keeps tension on the paper whether wet or dry.  Using a very stiff board  or an old hollow core door only results in partial release of tension as the paper tears slightly at the staples.  With these substrates I generally had problems with ripples when painting wet with 140 lb paper.

One of the problems with painting in acrylics as opposed to watercolor is that it can be difficult to make your backgrounds appear to be distant (atmospheric perspective).  Items in the distance need to be somewhat out of focus, bluish, and show lower contrast than the foreground objects.  What I do is paint the background with somewhat thinner paint (mixed with medium) then when the rest of the painting is complete add several thin glazes of light blue thinned greatly with medium and water (containing acrylic flow release or just water with a tad of Spic and Span).  This adds the bluish tint and reduces the contrast in the background. 

Most of us use reference photos in making realistic landscape paintings.  Although making an exact copy of a reference photo really contributes nothing to the art world, a well composed reference photo can save you a lot of time composing the painting.  Take a little extra time with your reference photos to get the composition right.  Maybe you will still have to move a bush or rock and add a few things but it it will save lots of grief later when your painting doesn't have much appeal because of poor composition.  Digital cameras really make this a simple process so you can take several "well composed" shots of your subject from which to select the best composition as a starting point. 

A low cost subsitute for acrylic flow release is to use a pinch of Spic and Span in a glass of water.  This is a surfactant like flow release which reduces the surface tension of water allowing the acrylic paint to spread evenly and wet the painting surface.

Typically I use a flat metallic pan with a piece of greaseless baking paper over damp paper towel as a palette. This works great for mixing small amounts of acrylics but doesn't allow enough space or provide containment for larger quantities.   For large mixes I use styrofom egg cartons.  These are pure white, washable and do not absorb water based paint like the paper ones.  Just  spray the paint with a water mist then cover with foil to keep several days.  I usually cut the cartons into sets of 6 cups each to make a size that is more convenient to work with.