$20 roll at cash games is a target..
Safest way to raise bankroll is tournaments and free-rolls. At the cash tables, if others see you only have a small bankroll, they will pounce, bully you with big bets.
But at a tourney, your entry(no rebuy tourneys) is the most you can lose, even if you are put on tilt. Free-rolls are time-consuming, low-payback, but if you play enough, you can get a small bankroll going
Avoid the cash games, because of the "credit card mentality." In cash games, you can have some bad luck, get determined to chase your losses, and use the credit card, which isn't healthy. As with anything, being cautious never hurts.