Get yourself an adjustable-range heat gun to remove the old stickers. Put your plastics out in the sun, let them get good and warm, then use ONLY the low range. It takes longer, but if you get to hot while peeling the sticker off, the first thing that will happen is the sticker will melt in half. No problem there, but that means you could be very close to burning the paint. and it happens fast. I got to practice on an old fairing first and learned that it only takes a second to make your paint look like burnt paint bubbles.
When putting on new stickers, have mildly soapy water (a little dishsoap) in a spray bottle for the bigger stickers. Lets you slide it around a little, and have a small square squeege to get the bubbles out.
One last thing, don't make the mistake I did by not having your work enviroment CLEAN. I got some dust under one of my big stickers and it shows when you look at it or wash it.
Unless you've done it before, try to figure out a way to do a practice run or two.