Now that you've done several signup offers, you need to start making sure that you're making a decent profit from each offer as you go along.
For each sign up that you do, try to make sure that you're finding decent bets, particularly for the free bets.
A qualifying bet should lose at most 5% of the bet amount. So if you were placing a £50 qualifying bet, your maximum loss should be about £2.50. There are a few instances where it's ok to accept a higher loss, particularly when betting with bookmakers who are prone to banning (like Paddy Power).
For free bets, you should be aiming to make as close to 80% of the bet amount as possible. So for a £50 free bet, your target profit on the free bet element should be about £40. This won't be possible on every bookmaker, but the majority of the time you can get between 75% and 80% of the free bet amount. Usually the easiest way to increase your profit on the free bets is to go for higher odds. If you back and lay a £50 free bet with back odds of 6.8 and lay odds of 7, it makes £39.62 profit. If you did it at back odds of 3.9 and lay odds of 4, it makes only £34.87 profit. These differences do add up.
Get value from your free bets - don't waste them.