If you own an apartment complex, then you're sitting on a potential investment that can be leveraged to pay your bills. You don't have to be on the property daily to earn money from your apartment complex. If you do a few simple estimates and calculations, you can determine the best way to make money and then take the steps necessary to operate the complex as best you can. If it's a large complex, you may want to consider hiring a professional management company. They'll take a percentage of your earnings, but they can also help you avoid trouble through their experience and contacts.
Hire an inspector to come in and create a list of everything that needs to be done for the apartments to be habitable. Get a quote on the work from a contractor. Go to an appliance store and figure out how much you will have to spend to replace or stock the apartments with the basic appliances such as ovens, showers, and toilets. Determine how much money you want to spend on refurbishing each apartment so that it looks nice. Take the total amount you expect to spend in maintenance and care and add that to a year of mortgage payments. Once you know the total amount of money you'll have to spend to maintain the apartments for a year, determine how much rent you'd have to charge if your building was 3/4 full to make ends meet and create a reasonable profit. This math will help you find out if it is feasible for you to manage your apartment complex. If you decide to go through with it, complete the repairs and make the apartments ready for tenants.
Contact professional leasing companies and see if you're satisfied with any of their rates. If you are, hire one. They'll take care of finding occupants, hiring staff and finding a maintenance person. If not, then you'll have to continue doing work on your own.
Decide how much rent you want to charge for the apartments. It should be enough to eventually repay you for what you spent on repairs, enough to pay your staff, enough to keep two maintenance people on call and enough for you to earn a living wage and turn a profit. Be sure that you're not overcharging for the location and condition of your apartment complex.
Hire at least two people who can deal with the tenants. They can collect the rent, deal with complaints, help with any evictions, and guide new tenants into their apartments. Also hire two maintenance people. You'll want someone on call 24 hours each day because there are some situations--like a utility breakdown--which must be taken care of immediately, according to the law in some states.
Set your standards for tenants. Decide if you'll allow pets and if you'll require a credit check or references. Once you know, and if you didn't hire a management company, then start advertising online and in the local paper for people to move in to your apartment complex. Offer a discount on the first month as incentive. Be available to show the apartments and answer any questions the future tenants may have. Once you have enough people living in the building, you'll be making money every month.