I always start by stamping my image with Memento Tuxedo Black. I do not heat set or emboss or anything special....I'm basically lazy ;)
I selected 3 colors of green and colored the stem and leaves. Keep in mind where your light source is coming from and shade based on that. I used the lightest color as a base and a medium to show areas of darkness and the darkest shade on tips of the leaves and base of the leaves.
Once everything was colored I used a stump dipped in gamasol (odorless mineral spirits, I use Mona Lisa brand) to blend and soften all my colors. I use one stump for each color family for ex one for greens and one for yellows.
Anyway, it's fun you should totally try it! I know you have some Crayolas so go get them and fall in love all over again. LMAO that was super cheesy.