Cheat: Infinite Skill Points
Note: This is very time consuming as it only allows you to get 500 points for every 1-2 minutes of play. You can probably get more points by killing the enemies normally, but this trick is available if you want to stock up on ammo, or fully upgrade one or two of your weapons.
Shortly after you and Trishka seperate from Ishi on your way to meet the General, you will come to an area where you will find a newsbot, a dropkit and a metal sliding door that you have to open. The door leads out to a street with a bus that you need to leash into a gap to cross. Continue fighting until you get to a point where the Mechaton's tail smashes a barrier allowing you to continue by hopping over a cement barrier. Walk up to that barrier, but do not hop over as you will not be able to get back. When Trishka is standing next to you by the barrier, you then run back to the dropkit in the room and the newsbot should have respawned. As you are running back to the room you will see the game pause for a split second with the loading symbol (rotating circle of dots) in the bottom right corner of the screen just before you cross over the bus. If you dont see this, go back to the barrier and let Trishka catch up to you. If done successfully, the newsbot will respawn indefinitely, giving you unlimited Skill Points at 500 points a kill. All you have to do after killing the respawned newsbot is to return to the cement barrier and allow Trishka to catch up to you, she has to come to a stop next to you or the bot wont respawn.