You're getting two conflicting types of advice in this thread. Let me try to sort it for you. (One thing you will need to figure is how valuable any particular type of mile or point is to you. However, for now, let's assume an airline mile is worth 1.5 cents.)

CHOICE A:
Sign up for lots of credit cards, specifically for the signup bonuses, and cancel most of them after 11 months. If done the right way, this will not damage your credit and you will earn tons of travel. As a newbie, you could easily score 300k+ of miles. At 1.5 cents each, that's worth at least $4500 in the first year. The annual fees are irrelevant - most waive it the first year and if not the signup bonus easily makes up for it.

CHOICE B:
Maximize only what you spend on a daily basis, over one or two cards. If you're spending, say, $2000/month on cards, then you can earn about 30k in miles in a year. Those would be worth about $450. Your alternative is a 2% cashback card, which would pay $480. Unless you travel a lot already, for most people, daily spending makes more sense on a 2% cashback card, since it takes so long to earn enough for a free ticket otherwise.

So which is it, SkiesBlueH20? Which path is yours?