Article Source: Marion Body-Evans (About.com)
Acrylic Painting Tip 1: Keeping Acrylic Paints Workable
Because acrylics dry so fast, squeeze only a little paint out of a tube. If you're using a 'normal' plastic palette invest in a spray bottle so you can spray a fine mist over the paint regularly to keep it moist. 'Stay-wet' palettes – where the paint sits on a sheet of wax paper place on top of a damp piece of watercolour paper – eliminate the need to do this, but generally don't have a hole for your thumb so are more awkward to hold in your hand.
Acrylic Painting Tip 2: Blot your Brushes
Keep a piece of paper towel or cloth next to your water jar and get into the habit of wiping your brushes on it after you rise them. This prevents water drops running down the ferrule and onto your painting, making blotches.
Acrylic Painting Tip 3: Opaque or Transparent
If applied thickly – either straight from the tube or with very little water added – or if mixed with a little white, all acrylic colours can be opaque. If diluted, they can be used like watercolours or for airbrushing.
Acrylic Painting Tip 4: Acrylic vs Watercolour Washes
When an acrylic wash dries, it's permanent and, unlike a watercolour wash, is insoluble and can be over-painted without fear of disturbing the existing wash. The colours of subsequent washes mix optically with the earlier ones. A watercolour glaze can be lifted out using water and a cloth.
Acrylic Painting Tip 5: Think Thin When Thinking Glazes
If you want transparent glazes, these should be built up in thin layers; a heavy layer will produce a glossy surface.
Acrylic Painting Tip 6: Improve Flow Without Losing Colour
To increase the flow of a colour with minimal loss of colour strength, use flow-improver medium rather than just water.
Acrylic Painting Tip 7: Blending Acrylic Paints
Because acrylics dry rapidly, you need to work fast if you wish to blend colours. If you're working on paper, dampening the paper will increase your working time.
Acrylic Painting Tip 8: Hard Edges
Masking tape can be put onto and removed from dried acrylic paint without damaging an existing layer. This makes it easy to produce a hard or sharp edge. Make sure the edges of the tape are stuck down firmly and don't paint too thickly on the edges, otherwise you won't get a clean line when you lift it.
Acrylic Painting Tip 9: Washing-up Liquid with Masking Fluid
Masking fluid can be used with acrylics washes, as well as watercolours. Be sure it's completely dry before you paint over it, and don't paint too thickly over it or you'll have to scratch away the paint to get to the masking fluid. Masking fluid will work on paper and canvas, but do try it out first before using it in a painting to get a feel for it. Once masking fluid has dried in a brush, it's nearly impossible to remove. Dipping a brush into some washing-up liquid first makes it easier to wash masking fluid out of a brush.
Acrylic Painting Tip 10: Using Acrylic Paint as a Glue for Collage
Provided it's used fairly thickly and the item to be stuck isn't too heavy, acrylic paint will work as a glue in a collage.