This may sound like a silly question from a 23 year old.lol But I was wondering, what are the various ways of contracting an STD? I know of some of the obvious ways, but I wondered if there were any ways I do not know about as yet.

Depends which one - there are many. Some are transmitted mostly through penetrative sex others are from any bodily fluid contact, kissing, oral sex etc. Some can be just through skin contact, scabies and pubic lice (crabs). Genetal warts and herpes can be transmitted through contact with the skin lesions.

Here is a great all combos chart of what you can catch of which partner how.
SFCC :: STD Basics : STD Risks Chart

HIV and hep B can be transmitted from mother to child, by dirty needles or infected blood transfusion.

You're bi/lesbian if I remember rightly? A lot of women don't realise that they can get STDs from other women/ magically think they are protected. A dam is a good precaution.

I'd be more through but I've got to go- deadlines call! If no one else answers (which I doubt) I'll come back later.
EDIT here is a good site which details some main STDs, causes transission, treatent and prevention. There is also a link near the top which will take you to a page which will make you terminally celebate so be warned!
STD - Public Information Resource

Well... thats opened my eyes a hell of a lot more! Thank you! Quite shocking some of it actually. And yeah I'm lesbian, I don't use dental dams or anything like that. I am going to get myself checked out just to be on the safe side, I also asked my partner to as well but she took it as a bit of an insult. :S

Thanks for the reply!

Great answer, It's a wonder anyone has sex except with one's spouse!!