There are many different ways to blend with acrylics. Here's the most common 1. Use Water 2. Work thick 3. Work slow and in small areas working your outward 4. If all else fails be lazy and use a slow drying medium
Acrylics clean up loads easier than oil paints, that's for sure! And they dry pretty quickly so it's easier to layer them.
But the bad thing is, they dry pretty quickly so it can be a pain if you don't work quickly enough. You might want to invest in some retardant. As for mixing the colors themselves, it just takes some practice getting used to the particular paints you bought. Depending on the pigment quality of the paint, you might get different results. I'd recommend maybe making a color wheel out of your paints and see how they mix.
Also, some people feel acrylics can become a muddy mess when blending. This is entirely untrue unless you abuse black. Black can quickly become your worst enemy.
White is ultimately the most essential I've found actually, haha. Can't get a darn highlight to save your life without it. As for black, it's definitely a totally different story.
Don't know so much about the "not blending" bit, haha. Mine blend perfectly fine on the palette or the format, though it does make for a longer process when working up a piece any larger than 18x24". I switched to acrylics a few years back, and I focus on an extremely restrictive palette. Keeping with tones similar to the conventional red, blue, and yellow and backing away from distant pre-mixed colors is a good approach. Everyone has a different approach to painting with acrylic, but if you want to knock out a painting pretty quick, mixing directly on the canvas has worked wonders for me. It forces you to work faster, and you can get a lot done within an hour if your paint dries fairly quickly. I personally work with 3 brushes, a large brush for an under layer plane, and then I jump on top of that with a mid-range brush once that's dried, and then maybe later tighten up things with a tiny little brush. Not to mention you can define planes of color however you feel that you left behind before as you go along with a piece.
*wince* Hm....this is the first I've heard of this. I was told they were easier to work with then regular watercolours. Is there any specific brand I should look for?