Could someone point me in the direction of how to do the best paintbrush job, and the best brushes and paints to use?
Regardless of the paint or brushes you use, the biggest tip I can offer you for hand-brushing is to thin your paints sufficiently. I can lay down coats as finely as if I airbrushed them, when I have thinned the paints sufficiently.
I paint figures, both in toy soldier style and in matte finish to go with my models. I use mostly water-based acrylics, such as Andrea, Vallejo Model Color, Lifecolor, and craft store brands Americana, Folk Art, Apple Barrel. I use a wet palette (Redgrass Games), which ensures a consistent thinness, and lets me keep any colors I've mixed, across several sessions.
I also use Tamiya's acrylics, which are alcohol-based. I can't use these with a wet palette. Instead, I keep a little jar of Tamiya's proprietary acrylic thinner, and either dip the brush in the thinner, then pick up the color from a palette (eg, the underside of the jar lid), or I pick up the color and dip the brush in the thinner, and then apply the color to the piece. I don't use any other additives, like levelers or retarders. I don't discourage them, I just find I don't need them.
I use a similar method to use enamels, except that I use mineral spirits as the thinner.
As far as brushes go, I do use natural fiber brushes, red sable, particularly on figures. Because when you paint a figure, you want to be able to paint fine lines at times. That means having a brush with a fine point, but also with a good-sized head to hold the paint. It's like a fountain pen with a fine nib. The nib delivers the ink precisely, and the bladder is the reservoir of ink. Same thing with the brush, and water-based acrylics (or oils). I had to learn this over time. I started with small brushes, because I thought that would let me paint fine details With water-based acrylics, the amount of paint is so small that it dries before it his the target. So I watched my fellow figure painters and noticed the brushes they use. A 0 or 1 round is good for that precision, and brushes made of natural fibers, properly cared for, hold their shape the longest. Red sable in particular is judged the best for this. The one I'm using now is about 10 years old. After a session, I use a brush soap to clean the remnants off, and to restore the natural oils to the fibers. Just like using shaving cream with lanolin to treat a baseball glove.
With enamels, I find that I can use that small brush, with a small head and fine point, like a 00, because the paint stays wet.
Larger brushes are good for painting larger areas, of course, and in that case, I don't necessarily use my sables. Though I still like natural fiber brushes for that job, just personal preference.
Again, the primary thing is to thin the paint properly. If you thin your paints properly, then painting them by hand is easy.
Hope that helps!