I'm doing well so far, £108 profit since Thursday on 8 qualifiers and 7 free bets. Although minus £15 for my oddsmonkey membership.
Things I will point out that have tripped me up a bit:
Remember to use the right odds - qualifying bets usually have to be at least 1.2 some higher so read the tutorials on odds monkey or from the bookmaker.
Don't bet on things too far in advance as then your liability is held up at betfair.
Keep an eye on the use by date for your free bets.
Make sure you type in the correct stake on betfair, I've twice now slightly mis-typed by a few pence so not much difference made to the profit or loss but worth noting.
When sent reload offers make sure you follow the instructions - e.g william hill bet £10 and get 3x£5 you have to go through the link they send you to get the offer it isn't automatically applied just by betting £10.
If you see a red bet on odds monkey at low odds use it for your qualifier and you make a profit.
Remember to check your cashback sites as I keep forgetting.