Mm, well the main thing is using the right things in the right situation, if their lead is someting that wants to set up, you might be better off using another attack since they'll expect a sucker punch, and go for a status boosting move like Dragon Dance or Swords Dance. And Absol, while an offensive powerhouse, even in mega has pretty crummy bulk sadly. :I If you're gonna use a mega absol in singles, make sure you get it boosts so it can one shot everything, or dual screens so it can take more than 1 hit. Magic Bounce is a great ability though, so it will be a nice switch in or lead if they want to set up stealth rocks or sticky web or something.