I'm still playing and learning but here's one tip I got from the Cricut boards - don't waste time or paper doing a pink sheet of paper for the tongues, cut it when you're doing the white pieces, then use a marker or chalk to color it pink after.
For flesh tones I happen to have a shade that is working perfectly that I got in a cardstock pack at ACM - I'm pretty sure Nicole is the brand name, but the cover sheet is long since gone.
I've cut at least one of everyone except Chip and Dale, and I haven't gone below 3 inches. Even at 3 inches the eyes drive me batty. Goofy is particularly tricky because of his teeth. I did a full body Goofy at 4 inches and I still ended up skipping his teeth because they were just too small for me.
I love all the accents though - the Mickey gloves, shoes, etc. Those you can do in all sorts of sizes with no worries.
I've barely scratched the surface of what this cart can do! I'm so glad I got it!