Which Hands Should Be RFI?
As previously mentioned, hand selection and range construction are the first key components to developing a strong RFI strategy. Given that folding yields an expected value (EV) of zero, you want to choose to raise with hands which will have a positive EV.

Below is a chart outlining the RFI ranges for a 6-max table (taken from our free preflop charts), assuming effective stack sizes are 100 big blinds: