Make sure to look into what permits or licenses your event may need and start the applications process early.
Missing a mandatory permit is something that can halt your event in its tracks so do your research about what it is you'll need.
Some common ones to remember are:
1) Alcohol
2) Noise (If playing music or hosting live entertainment)
3) Health Permit
4) Business License/Vendor Permit
5) Fire Permit
6) Building Permit - Large tents will need a building permit to erect and also need an inspection. You tenting supplier can give you more details.
7) Street Closure Permit
8) Raffle/Bingo Permit
9) Race Permit