In Star Wars: Knights of the Old Republic, to defeat the Mandalorian leader Sherruk who is located on Dantooine, you should first start by going to the caves on the map south of the Dantooine Courtard and grabbing the lightsaber crystals to upgrade your lightsabers.

You should be using two melee tanks and one ranged character. I would recommend Zaalbar with a Vibrosword, Canderous with his ranged weapon, and another melee, either your main character, or Bastilla, though she may be a bit weak for this fight, a tank is better. Next, make sure you have grenades, preferably Plasma, concussion and a few frag grenades.

Also make sure you have energy shields equipped on your characters. Melee energy shields will help a lot, since Sherruk uses very powerful melee hits. When you're ready, head over to Sherruk who will be with a few other enemies.

Run to the right, but before engaging him, activate the energy shields on all 3 of your characters. Then get closer and Sherruk will talk smack before attacking you. Right when the battle starts, keep the game paused, and throw 1 plasma grenade, and 1 frag grenade at Sherruk, and have another character throw a Concussion grenade at the nearby enemies.

This way they will be stunned while you fight Sherruk. Now have all 3 of your characters focus on attacking Sherruk with everything they have. Make sure you get an advanced medpack off right away on the character Sherruk attacks, because he hits hard. Use power attacks, sniper shot to stun, and any other powerful attacks to take him down quickly.

Once he is down, the other enemies will be easy to finish off. Congratulations! Don't forget to back to the main courtyard and talk to Jon for your 1000 credits and light side points reward.