My third tip...Just Fake It!
Thankfully along with the line stamp trend came watercolor. With watercolor, you can fake it! My favorite watercolor technique for line images is to heat emboss first (this contains the water) then add color with Distress or Zig markers and spritz with water (or add water with an aquapainter). The water does all of the work and you get a beautifully watercolored image. Here I used Zip Markers and just scribbled a little bit of color onto each leaf. I didn't color it in, it was just a small amount of color. Then I spritzed it with water and done! See, I didn't even have to know what I was doing, I totally faked it. A Kindergarten could easily master this idea ;)
I used the same technique here. The results are really stunning! I hope you'll give it a try!