Mega Sharpedo :

• Crunch : Main dark STAB that got boosted by jaw.
•Waterfall/Close Combat : Waterfall for water STAB against Ground and Fire type or Close combat to hit other dark type.
•Protect : Stall 1 turn to gain speed boost as base Sharpedo.
•Psychic Fangs : Boosted coverage move for Fighting and Poison type.
•Ice Fang : Coverage for Lando, Mence, Gliscor, and other mons that 4x weak to ice.

Note : ALWAYS gain speed boost first before mega evolving so you can outspeed stuff. Treat mega Sharpedo as late game cleaner because it cant really sweep things unless its an extremely good match ups.