Tip #1 when I am applying my base coats I tend to do a mix of 3 to 1 color and water. This way I get a smooth even coat. It may take 2-3 coats but it saves your piece from getting weighted down and also prevents the lines.

Tip #2 If you do end up with lines or high edges from your brush strokes you can take a paper bag and go over it to smooth it out some in between applications of paint. (Make sure no printing is on the part of the bag you are using.) Sometimes you have to lightly sand it. But if you use my base coat technique it prevents obvious brush strokes.

Tip #3 I keep a washcloth at my paint station I use it to clean my brushes as I am painting. It's washable and I can use it over and over. I also keep a rather large container of water right next to my rag. Makes it easy for floating and washing...

If you have any tips you would like to share please post them here for others to see. I have others I'll just have to think of them. Have a great day!