a) to think what "group think" is doing to the prices at half time, and see if there's value in the opposite.
b) to not do a single bet at odds-on (although a portfolio of bets can be).
When I can't find an angle for my £100, I look for a "hey who knows" tenner. Which tonight goes on West Ham at 30/1ish.
My usual plan is to go green if things go in favour, but the tenner bets are more hit and hope, so we only go green if West Ham actually take the lead.