Tatsugiri can be scary after +1 speed and +2 special attack soo..

•Hydro Pump/Surf : Surf for reliable water STAB and hydro pump for gambling + high base power.
•Rapid spin : to clean hazards and raise your speed.
•Draco Meteor/Dragon Pulse : Meteor for the high base power STAB and pulse for those who wants to avoid -2 spa.
•Nasty Plot : Increase Tatsugiri spa for bigger damage.

Items
•Life orb : If you're greedy, run this to increase the dmg even more.
•Duty boots : to avoid hazards and stay healthy.

Note : Rapid spin first then Nasty plot and kill as much as possible (sweep if you can).
If Tatsugiri already kills 2-4 mons, dont be afraid of losing it.