Here are a simple few...............
(1) You don't hafta buy all of the weapons - in fact, do NOT buy the AR Rifle OR the Machine Gun. I'm just saying.
(2) Mutant Bash TV (the first run) - do NOT go in there without less than 100 Pop Rocks and either turrets or bots. Don't say I didn't warn you.
(3) Save your loot from all of the missions until you get to Wellspring - if you feel you hafta sell off your loot before Wellspring - you have no project management skills. In other words, see items 1 & 2.
(4) This is just a warning, and that's all: The Cuprino is a POS. It drives like a fully loaded garbage truck in 4 feet of mud. Just think about that for a minute.
(5) Invest in shotgun ammo, and fatboys - you'll thank me much later.
(6) Sell everything you don't use, do NOT sell anything you need. Welcome to ID games.
(7) Last but not least, the game is over way before you get to the end game. Play it non stop, and tell me I'm lying

At this point in my Rage experience, I quit playing and restart just about the Blue Line. The first third of the game is awesome - its fun, its on top.
The last third - not so much. I haven't seen Capital Prime in months.....lol.
I have more to divest, but I will save it for a later date.
Cheers buddies.