Wow I used to know so many people who dress like this! Ah those were the days.
Ahem, yeah. Too much makeup looks ridiculous no matter who you are. A subtle bit of pencil eyeliner on the top and bottom is fine, it doesn't look like your trying to hard.
You can get all those chains and stuff pretty cheap all over the place, if your american would Hot Topic be the thing?
Those boots are as expensive as fuck, by the way. The standard goth boots that most people have are called 'New Rock' and average around £100 [$200] but I'm sure you could find some sort of cheaper version. But I know for a fact that New Rock shoes last FOREVER, providing your feet have stopped growing.
Other clothes are easy, black pants and a black tshirt, for starters. You can elaborate on that later, maybe with t-shirts of bands or something [just make sure it isn't Westlife
xD]
I have a katrillion of those spikes from my goth days, enough to cover both arms xD It's really quite intimidating but nobody messes with you! One thing I would say is, you can't type on a keyboard or write with them, and having lots can actually get pretty heavy. Stick to one on each wrist to begin with.