Go For 3 System
You will be tracking a 37 spin session. Every time a number repeats, you will bet that number through the end of the 37 spins. You will usually end up betting around 7-8 numbers by the end of the session.
This is based loosely on the law of the third. Basically, it states that within a 37 spin session you will only see, on average, 24 different numbers. This means that on average there will be 13 repeat numbers, and there is a good chance that those 13 repeat numbers will not all be different (thus some numbers will hit 3, 4, 5 and even 6 times) and you are trying to cash in on this.