I was just wondering what are some big things to look out for switching from regular tenor trombone to bass trombone. I'll probably be doing that just for my schools jazz band but still playing tenor trombone for concert. Give tips please

It's a whole different animal. You have to treat it as such.
Keep in mind your positions will be longer than they are on tenor. Intonation will be a challenge for a while.
You will need to do exercises to develop facility with the triggers. It will get confusing, believe me.
You will use a lot more air.
Get some lessons from someone who plays bass trombone as their primary.
There's a lot more to it, but it can't really be taught online.

I have learned that bass actually helped me a lot. Since it requires a lot more air, i never had air problems since then. and what you get from the low ranger on bass you can do on the tenor, so it helps you there as well.

I had fun learning all of the triger positions

I just started playing Bass Trombone this year as my primary instrument at the University. I had played trombone and tuba before, but the bass trombone is unlike anything else. It will take an outrageous amount of air to play it properly, I have personally equated it to the amount of arr required to play a trash can. If you don't use enough air your sound will be weak and thin, exactly the opposite of what a good bass bone (especailly jazz bass bone) would be.

To get yourself comfortable in the lower range start at about F in the middle range and work your way down chromatically playing two full rich quarter notes of each pitch, taking a two count rest, and continuing on down as low as you can go and then a little farther. If you do this religiously you will be amazed at how quickly this will extend your lower range.

And as others have mentioned, intonation is going to kill you on a bass trombone. Sit next to a piano and tune every one of your notes below Bb in the staff, those will be the hardest. If you have a big mouthpiece like I do it will make you flat on just about everything above F in your mid range, so tune each note.

Talk to someone who is good at trombone to get good positions for notes with triggers, keep in mind that when you use one or both of the triggers you have to add on about one position to where you would logically think the note would be. For example, a Eb below the staff is best played with the F trigger and about 4th (rather than 3rd) position.

when you play pedal tones, DON'T PUFF YOUR CHEEKS STAY CONTROLLED... this is absolutely the most annoying thing I can think of in band. Sure it requires more air, but if you get used to bass trombone and go back to tenor, there's a good chance you'll be overblowing the horn unintentionally. The more your practice your extreme ranges, both high and low, the more controlled your mid range will sound. I just made my account, and i'm going to upload some mp3's of my highschool's jazz band.. And I am the lower trombone that sticks out a bunch... lol.

nevermind, this dumb site keeps telling me that i'm uploading an incorrect file when it says mp3 and i'm uploading and mp3.. woo.