Partial engine failures carry a much higher fatality rate than total engine failure and yet, statistically, are 3 times more likely to happen (from an Australian study which I don't have to hand right now).
So think about how you would handle losing significant power on the climb out after take off and practise such scenarios.
Also if en route and you experience a significant loss of power head for the nearest airfield maintaining (or even gaining) height and on reaching the overhead close the throttle and perform a forced landing there. If you opt for a normal join the engine might quit halfway round the circuit. Of course you also need to apply usual judgement in having a look round for cause of failure and do stuff like switching the fuel pump on, if applicable, and change fuel tanks etc. Beware "get home itis" and trying to return to base too whilst you pass safe landing sites.