I'm sure you've seen other posts about this but maybe you haven't bought it yet. I LOVE Reynold's parchment paper (there's probably some other brands, feel free to look around)! I have an airbake cookie sheet (got it a looonng time ago) and it's sorta scratched and yucky looking but when I put parchment paper on it I don't worry! :) Plus if you're baking cookies, you can probably scoop those cookies off and use the same paper again (saving $) for the next ones to go in the oven (cool your cookie sheet a little). The parchment paper really helps so you don't have to scrape the cookie sheet or possibly wash it between uses (did I really say that? do I sound a little lazy?). Look here for a free sample!
I also use parchment paper to line my square airbake pan (again, bought a loonng time ago) to bake brownies. It doesn't fold into the corners perfectly but that's ok, I usually cut the edges off (we keep and eat those) and send the cut up brownies for functions and gifts. I think brownies are best when frosted (yum, I promise it's all my husband's fault!!). Take a regular can of frosting, stir it, then frost semi-cool brownies (spread the frosting around before you cut them). If the brownies are semi-cool the frosting will "melt" a little and be really delicious. Another tip is to take a box mix and add 3 eggs instead of 2. This makes a more "cake-like" brownie (according to the Betty Crocker directions). I also recommend baking in an 8x8 or 9x9 square pan instead of 9x13. With the added egg, this makes the brownies much thicker and it seems to cook better (softer and not overdone). (Put the leftover frosting in the fridge, use it for your next batch of brownies, ice cookies with it, make smores, or frost graham crackers. I've left my leftover frosting in the fridge probably up to 1-2 months but the label will usually say 1-2 weeks.)
Enjoy! And these ideas, work for me! See Shannon for more tips. :)