1 simple word......


grenades.

I would recommend leveling whatever your lowest weapon is. Try to get all your weapons up to the same level and then level them all at the same time. Bosses are great for this--take a crew for healing AND a crew bonus, or just find a good spot where you can attack a boss without taking too much damage (cliffs, second stories of buildings, etc) if you're going solo. I'm not a big fan of glitching into a wall, personally.

If you do it right with the right enemy, you can get 100+ points for each weapon you use on an enemy.

Check out this thread for the details.

Good luck, mate!

Nades
 

I'm standing in front of General Darkhart on
Padres Back Beach right now. There is a ramp
that leads up to him. In front of it are 2 rocks, a
large rock and a small one. Stand on the small one
and take 7 steps backwards. From that spot u can
throw nades at the General, he will attack u with
several throws of his daggers then switch to his
cutlass. At that moment he will stop attacking.
You can stand there and throw nades and throw
daggers at him till the cows come home and he
will not attack you. That's because he is a raider and
they have a particular glitch that causes them to
stop attacking when you are a certain distance from them
when they switch from daggers to cutlass attacks.
Why no one has told you this particular trick in the
past I am not sure but it works both on test and open
servers and is more useful in nade training. GL

^^
Either this trick or get on the house next to Darkhart. I only use the bottom of the ramp if theres like tons of people who won't fit on the house grenading him. At the bottom of the ramp, the only things you can do is throw nades & daggers & shoot bullets. Coz if you grenade him from the side (not the roof) on the house on the left in the picture, Darkhart will be close enough so you can Throw Dirt for Dagger & Taunt for Cutlass in addition to the stuff mentioned before, so you could work on your lvling for nades, daggers, gun & cutlass.