Getting your security deposit back begins on the day you move-in.
Before you move any furniture or personal items into the space, take a note pad and a camera and go through the apartment thoroughly.
Document anything that looks like damage.
It is helpful to use a camera that automatically date stamps the photos, or, if you're using a video camera, say the date and time clearly at the start of the video.
Don't wait to send this to your landlord.
Give your landlord the documentation right away.
This will alleviate any misunderstandings that might otherwise occur at the end of the lease as to when the damage took place.
It also shows the landlord that you mean business about getting your security deposit back.
When you move-out, you should repair damages yourself.
This could be as minor as putty-ing up holes in the walls where you hung pictures or snaking the shower drain.
Give the apartment a very thorough cleaning.
Make sure the landlord has your forwarding address, and if necessary, the forwarding addresses of your roommates.
Your landlord must return your security deposit, oftentimes with interest, within a certain period of time as designated by your lease and by the laws of the state in which you are living.
Your landlord has the right to keep any amount necessary to repair damages beyond ordinary wear and tear, or pay off any debts related to the tenancy.
If the deposit hasn't been returned with interest within the time frame set out by your lease, or an explanation hasn't been sent otherwise then send your landlord a certified letter.
If the landlord doesn't return your security deposit in a timely fashion, then you will have to take them to small claims court in order to claim the penalty.
Many cities have free legal services to people who are having trouble with their landlord, and a quick search on Google will turn up your best resources for going to small claims court.