This will probably be split into multiple topics at one point, but for now, here are some tips I know for painting props, signs or really anything. It’ll be condensed as I’m just trying to get my thoughts on here until I can really flesh it out.
Paint dark to light. Always.
The darkest color will represent the medium you are working with and the base of your project. The lighter layers will be your mid-tones and highlights.
Think of a tree. Your base will be black or really dark brown. As you work in your layers you will include other browns in various shades, but they will always be lighter than the base.
Mix brushes, rollers, rags or any other object you are using to paint with.
A friend once asked me why I only use a brush or two on a project that would normally take many more. My answer: I just like the results.
That sounds odd, but when I work on a project I never clean my tools until the project is finished. You will find when you mix your colors and tools you can get some great results.
You can take a look here. Not a great picture to demonstrate the results but by using a single roller that was initially used for black, then gray (see, dark to light), it added something special. A texture that shows wear on the tub that otherwise would have had to use multiple layers to achieve.
Plastic bags can be your best friend.
Following the nonsense from above, store used rollers or brushes in Ziploc bags to use further down the road. Obviously take a bit of caution with this as if you are not going to be using the brush/roller anytime soon then it would be a waste to try and preserve it. I generally try and follow this when I know I’ll be doing multiple projects over the next few weeks.
Add dirt, sand, gravel, etc., to your paint when you want something to stand out. One of my latest projects I used oatmeal to add a sort of ‘vomit’ type texture. An example can be tombstones. People use Drylock to add that stone texture to them.
Point is, experiment.