I personally think that a good way to solve the problem with starting your deck is to make a dozen or so cards yourself, to give an idea of how you want it to work to the other players. It might also help explain to the other players that the object is not to win. I could send you pictures of some of the cards from my Suck Box so you can show people what not to do, if it helps. I can see how, to someone used to playing more competitive games, the initial response is "what's to stop me from making a card that gives me millions of points or makes me win automatically?" You have to either explain that the point of the game is to make creative cards that other people can reuse in the next game, or you should just find something less demanding.
If they need a rule of thumb when making cards, my general guideline is not to make a card if the game would stop being fun if someone else played it. This covers instant-win cards, which usually nobody else likes, and overpowered effects, which you wouldn't want someone else to play.
Oh, and I cut the index cards in half 10 or so at a time with a paper cutter, and I don't usually want more than maybe 40-50 blank cards to start, so I don't need to cut every card at once. I've also heard of people who use A7 size flash cards (which is why I started geeking out about the mathematics of designing paper standards).