You must show a secure and stable employment history. You must have good credit history. You must have a social security number. If you do not have a social security number or are not in the process of applying for one you must have a guarantor co-signing your lease. You must show a good rental history.
All information has to be referenced in form of a letter or sometimes a phone call.
For business owners tax returns will be required. All students must have a guarantor to co-sign their lease. Or some owners will allow you to prepay 6 months to 12 months rent up front. Once you have found an apartment, the next step is to apply and then sign the lease. Generally, you will need to leave a deposit equal to one month's rent which is fully refundable in case you get rejected.