I've seen people say one of the biggest differences between bass and guitar is the left hand technique. What are these differences? I recently switched to bass from guitar and I don't want to develop bad habits.
i don't think so...
i started on bass
and moved to guitar
and they are BASICALLY the same left hand technique
you just fret the notes exactly how you would on a guitar.

now, your right hand is COMPLETELY different, unless you use a pick
but you cant play slap with a pick,
and you will get a smoother sound if you use your fingers

i play with my fingers usually, unless im playing slap, then i play with my whole hand pretty much..
just do whats comfortable though man
i play an 8 string
There are some differences.

1. Strength and stretch. Don't compromise. And fret buzz is a bigger problem if your not landing correctly behind the fret.

2. Watch that thumb. It shouldn't be over the neck towards the fretboard. There should be some air between your index and thumb when you hold the neck. The thumb becomes a pivot point for you, esp. if your hands are smaller.

3. Fretting arm. Get it closer to your body than you did as a guitarist.

There are others, but I am tired, can't think of more and I really need to get off this computer and go to bed...