Well, just remember, each A/C is different with respect to steering linkage connect/disconnect (the pin). For example, if I remember right, on the ERJ 135/140/145 series, the nose gear disconnect is electrically activated via a switch in the ground power connection panel, just fwd of the main cabin door.
Re: Engines -
You will know when they're running/not running. Just like you're familiar with a GA ramp and you can tell when a turboprop shuts down but is still windmilling, same thing with a large jet. The major difference is that the airliner is usually going to be noisier. This is going to sound really stupid, but the way I was trained for hoover jet safety was to react as if I had caught fire: stop, drop, roll. If you feel like you're getting sucked into the engine - Stop approaching the engine, Drop to the ground, Roll perpendicular to the engine. Caveat... I've never attempted this, nor have I ever placed myself in a situation requiring this, but it made sense to me and it's good to file away for future reference.
Gear:
Good light is a must! My preference is the Streamlight Stinger. If they'll let you have a leatherman, go for it, but I wasn't allowed to bring it through to the AOA... friggin crazy. Also, my glove preference is mechanix wear, the fast fit reinforced kind.
I guess the best advice I can give is to never become complacent and perform tasks automatically. Keep your mind engaged at all times and you'll be fine... and probably become a L.A. in no time.