Be sure to have corn starch & powdered sugar available for dusting the rolling surface
I used a 1:1 mix...and don't get carried away with too much. It gets absorbed into the fondant and stiffens it.
Have a soft brush available to brush away the excess powder.
Depending on how large you're planning, roll the fondant on a large piece of heavy (heavy, as in upholstery weight) plastic so you can lift it over the cake.
You'll need to ice the cake first with buttercream to get it to stick. it only needs to be a crumb icing, but I always add more since some people pull off the fondant. Folks tend to forget that bottom layer since they "think" they are icing it in fondant. Fondant's just the "pretty on top."
Chill the cake iced with buttercream and then use your hands to smooth the surface. Your body heat will be just enough to take off any ridges that would show through the fondant.
Don't roll any thinner than 1/8" or you'll see every pimple on the cake. On the other hand, don't get carried away with 1/2" thickness. Then you won't be able to get nice edges. I used dowels on either side of my rolling pin to keep an even thickness.
Use a smoothing tool to buff and made the fondant adhere to the icing.
Never tug. It won't work. Lift and drape. Repeat after me: lift and drape.
You can add any color you want, but the darker you go, the more crap you'll have to add. Take a small chunk and add your gel color to that. Then blend that darker piece into the rest of the fondant, rather than adding the gel to the entire chunk. The color will distribute more evenly.
To make stripes, roll out two foot-long 1/2" thick snakes of different colored fondant (like red and white). Lay them side by side and cut across into 1" pieces. Swap out every other piece and slightly squeeze the snake to get the alternating colors to adhere. Now roll it out. The stripes will widen as the fondant is thinned out.
To adhere "fondant to fondant" (like putting yellow fondant daisy flowers on top of a white fondant covered cake) brush the bottom of the flower and press to adhere. You're using sugar to glue sugar.
A trick I've seen in books but never tested is to mist the finished cake with water to remove all excess powder and then use a heat gun to remove the moisture.
Okay, that's it. You've tapped me out.