Finding an apartment you like is just the first step. Then, you need to be approved to rent the apartment. Being turned down does not necessarily mean there's anything wrong with you as a renter. Sometimes, there are just 20 good applicants for the same apartment, the landlord can only choose one person, and it happens not to be you. However, you can at least take some steps to help ensure your application is as solid as possible, thus increasing your chances of approval.
1. Provide proof of income.
Whether or not the application specifically requests it, provide proof of your income. This could be a W2 if you have a traditional job, or it could be a 1099 if you are an independent contractor. This will make your application stronger than if you were to just write that you make $XX per year and expect the landlord to take your word for it.
2. Submit your application early.
If a listing says applications will be accepted until Sunday, make sure you get yours in well before then. Some landlords just read the first few applications they get, pick out a reasonable tenant, and then discard any future applications they receive. This may not be fair, but it is the reality, and the best way to deal with it is to just get your application in early.
3. Provide good references.
Think long and hard about who you include as a reference. The best references are previous landlords or roommates. Friends and family members are not as strong as references. On your application, note how you know the people you list as references so the landlord knows who they'll be calling. For example, write "Jane Doe — Previous Landlord." If a previous landlord is willing to vouch for you, then it will be more clear to your potential new landlord that you're someone they want to rent to.
4. Ask if the landlord would like to know anything else.
When you turn in your application, be sure to ask the landlord if there is anything else they want to know. Invite them to call you if they think of any other questions. This shows that you are open and honest, and it also helps ensure they don't pass over you simply because something is unclear.
If you put the advice above into action, you will increase your chances of being approved for any apartments for rent you are looking at.