I'm repeatedly asked what sort of tools and paints are required in order to prep a raw kit, so here's a collection of my favorites. These are my preferences and I don't endorse any particular product or company professionally. These are just my opinions!
For the casual costumer I recommend you grab a cheap rotary kit with a variety of tools off. I picked up the Wen kit below off of Amazon.
I've upgraded to Dremel brand items in the past, but I put mine to so much use that I tend to burn them out. It's far less painful to replace a $17 set! I do, however, generally stick with Dremel brand bits. One big recommendation I do make is to stick with plug-in units. The battery powered versions don't pack enough punch for heavy trimming or sanding.
If you want to make your life easier (and your hands happier!) grab a palm sander like the one below, and a variety of different sanding sheets. Hand sanding is great, but a mouse is much faster. I generally start with an 80 grit and work my way up to a 400 depending on the particular piece. I personally own Black and Decker's Mouse sander and have yet to replace it after two years of serious use.
Make sure that you sand off any shiny spots of the cast. I personally don't use mold release on my pieces, but many casters do. If you don't do a thorough job of getting it off, you have trouble getting your base coat to adhere. I always keep hand sanding blocks around as well as dental file tools to help get into the nooks and crannies.
Three things that are always in my shop are Zap a Gap, Zip Kicker, and a glue gun. With CA (the main chemical components of Superglue and the like) you want to keep it minimal. Less is more. Zip Kicker helps it set more quickly but also keep in mind that it's a chemical reaction that causes heat. You can burn your fingers if they are covered in CA and you hit it with Zip Kicker!
Then there's the ever present glue gun. I use a high melt version now that I have a lot more experience but I have gotten a few nasty burns due to carelessness. I suggest you go with a standard gun until you get some practice. I'm also an advocate of leather gloves when working with these! Hot glue is great for adhering visors into place or filling in the edges of pieces. Keep in mind that it can generally be removed with heat, so it's not always the best choice.
A good base coat is everything. I'm a big fan of Krylon's Fusion paint for plastic. Since most of my pieces are made of some form of it, this really ensures the base coat adheres properly and without bubbling. A cheap paint for a base coat is likely to give you cheap results. Now, I occasionally want something to look rough, so I keep a wide variety of rattle cans around. Rustoleum makes some great hammered effect metallic and I usually keep a generic $1 can of black around for quick and dirty weathering. Please note that temperature affects your spraypaint! Freezing temperatures are particularly awful in that the cans tend to clog up and thicken. I ALWAYS SPRAY ON A BLANK PAGE BEFORE I SPRAY MY PIECE!
I use an airbrush for most of my detail work. I've yet to find a favorite and do a lot of custom mixing to create my own colors. If you decide to go this route, I'm a big fan of Paasche's brushes due to the customer service and relatively inexpensive replacement parts. I strongly recommend that you invest in a compressor as the compressed air cans freeze quickly and gum up your paint.
There's also a large box of various acrylic paints laying about. The key with using these is to keeping them at a good consistency, so make sure you thin them a bit before use.
If you are not careful, you can ruin your entire piece with this step. Again, I use Krylon's clear coat products. As with your base coats, test the can before touching your piece, and apply in thin, light layers. I've heard that if you immerse your can in warm water it will provide a more even, fine layer, but I've yet to try it out myself!