For the skills, fundamental skills are Diva Inner Glow Hard to Get Quicksilver Slayer Silent Resolve Hit and Run High Velocity
Mind Games also help with the minions, but they are not as important in this fight compared to all the other battles.
Slayer has been far too overrated, but that's because the description is totally wrong. It doesn't add 25% overall critical damage. It adds 62.5% base weapon damage to overall critical damage. So, for an enemy that takes high damage from critical (basically, having a very weak spot), this damage becomes marginal. But criticals are the only way you can damage Crawmerax, so you might as well take Slayer.
Before you start the fight, make sure you have similar equipment listed. Get a feel of the battlefield. Learn how to destroy all the minions except for armored craw worms. Familiarize the layout, and learn to hide behind those pillars.
You might fail a few times at the start. First few times I played, I didn't lose to Crawmerax. I lost to the cliff, because I wasn't watching where I was going, lmao.