I offer this advice before you get involved in miles/points-earning schemes. Since you are a college student, I shall assume your income is modest; if you are a trust-fund kid, read no further.

Most points-earning schemes involve some brief period of illiquidity. A simple example is the US Mint $1 coin gambit. The US Mint charges your card for the amount of the coins, say $1000, but you do not have the coins in your possession until a few days to a week later. And $1000 worth of dollar coins is useless for paying off that same $1000 credit card charge, so factor in a couple days for finding the time to run to the bank. This is a minor inconvenience, but other schemes can tie your funds up for 30-60 days. The point I'm getting at is:

1. Make sure you have enough cash to cover the charges you make, independent of the money involved in the churn itself. All it takes is a single finance charge on a credit card balance that is tied up mid-churn to make the whole deal a waste of time.

2. (A corollary to #1) Know your credit card billing cycle close dates by heart, and use them to your advantage. Time your churn to start the day after your billing cycle turns over, to make sure you have the maximum grace period to work with.

I truly don't mean to sound patronizing, so forgive me if I'm overstating the obvious. I don't know your personal financial affairs or your degree of fiscal discipline. I do, however, remember what it was like to get the points fever when I was in college.