Rafflecopter: This is similar to what your Rafflecopter will look like: https://www.rafflecopter.com/giveaway We use it to help you gain more followers, by having them tweet a message about your book, visit your Facebook page, and follow you on Twitter for entries. You can get slightly more complicated by having them follow your newsletter or what have you, but honestly, the verification becomes a little more difficult--and entering into the contest is supposed to be fun and easy, so you don't want to make your entrants work too hard for a chance at the prize.
Author Takeover: This is generally done in a Facebook group or event. Usually it's done to celebrate a new book release or maybe a holiday type event--like paranormal books on Halloween. You, as the author, would "host" for about an hour. Generally you'd post a contest ("Post your favorite book title below and I'll choose one lucky commenter to win a free e-copy of my book."), some memes, a little bit about your work and ways to follow you, in case the people that joined the event would like to follow you.
ARC: An ARC is an "Advanced Reader Copy." It's generally a copy before the book is published, but after it has been edited, and is either awaiting copy editing or release day. Since this is the copy the bigger reviewers see, you want it to be as pretty as possible.
Press Release: This is the letter we send out to the press. It has to be short, of interest to them, and make your book seem like something they might want to read/be interested in publishing in their paper.
Keywords: Generally when we talk about keywords here, we mean the search terms used by Amazon, and those are our focus.
Categories: Again, this is reference to Amazon categories, or the genre sections in which your book can be placed.