The following is a very time consuming way of racking up skill points:
After you and Trishka separate from Ishi while on your way to meet the General, you will reach an area with a dropkit, newsbot, and a metal sliding door. Open the door. There will be a street with a bus that you need to leash into a gap to cross. Keep fighting until the Mechaton's tails smashes a barrier that allows you to keep hopping over a cement barrier. Go toward the barrier, but do not hop over it as you will not be able to go back if you do. When Trishka is standing next to you by the barrier, run back to the room with the dropkit and newsbot will have respawned. While running back to the room you should see the game pause and display the loading symbol in the bottom right corner of the screen jsut before you cross over the bus. If you do not see this then go back to the barrier and let Trishka catch up to you. The newsbot will respawn indefinitely, giving you infinite skill points at 500 points a kill. After killing newsbot return to the cement barrier and allow Trishka to catch up to you. Repeat the process as many times as desired.