First of all, I'm going to assume you have a little capital to work with, say $10-20,000.
For starters, you need to find a real estate investor who is older than you to mentor you and give you advice.
Don't EVER borrow money from the bank to use toward income-producing assets. I know you've heard it before: "The rich use debt to make money." Well, the richer ones use investors to make even more money. Be like them. Find investors and invest time yourself.
The best property to start off with is a single family home. Simple, only a few rooms. It's better if it's foreclosed, if you can find one.
Try and find where the next "Big Place" is. When real estate space fills up in a large city, everyone starts expanding to the outskirts. Try and pinpoint the next place where everyone will be, so you can get the real estate cheaper and then charge the same rent everyone else is charging.
Remember, don't buy the best house in the worst neighborhood. Buy the worst house in the best neighborhood.
At this point, you'll have to put in a ton of sweat equity into it, like painting, and repairs, because you have only a small amount of capital. That's OK. We all started somewhere. Have an inspector check the property to make sure it's structurally sound. Cosmetic issues you can fix yourself.
Don't EVER try condos. You'll hear the scary stories of people who get stuck with them. I won't get into all the technical details of why to avoid them, but at this stage in your career, stick with single family homes.
Make sure the property is in a good school district. It doesn't matter if the property is great and cheap, if it's in a bad school area, you're not going to get anybody willing to rent it. And if you do, you're not going to be willing to rent to them, if you know what I mean.
Put the most effort into the Master Bedroom and the Kitchen. Put crown moulding in the bedroom and good countertops in the kitchen. The wife of the renter will fall in love with them.
ALWAYS do a credit check and a background check on your future renters. Be wary of the ones who keep repeating and repeating, "We're good people, we're Christians, we don't steal," etc. They will also need references. I'm telling you, if they're not good people, they won't pay and they'll destroy the house. And it will be a nightmare to try and get them out.
For the deposit, don't call it a deposit. Call it last and next months' rent.
Selling property you purchase and fix up is not always a good idea. If you sell it, then all you have is a lump of cash. It doesn't do you any good sitting in the bank with interest rates that suck. You have to make sure that your money is working for you. If you rent out the property, you make money every month, and still have an asset. Brilliant, really. My great-grandfather owned a building downtown in the late 1930's and early 1940's. My great uncle sold it for a small sum later on. Today that area is considered the best and that building is now a series of elegant stores and a very expensive hotel with a five-star restaurant. Imagine if it hadn't been sold. Our family would be collecting the rent, which makes more in one year of dues, than the selling price of the building in the 60's.
I've also been looking into Real Estate Investment Trusts (REITs for short). These enable you to buy a share of property, much like a stock, and you get payed monthly dividends. I've seen some where a share costs $6-7, and the monthly dividend is $0.42 or so. Which doesn't sound like much, but if you bought 2,500 shares ($17,000 worth) you'd be making $1,000+ a month of dividends. I've also seen "crowd-funded" real estate where you can invest in Manhattan property. I'm not sure how similar it is to a REIT, but it's probably worth looking into as well.
You could also do what's called "House Hacking". Buy a property near a college, and rent out EACH room to college kids. You'll collect 3-4x the rent you would from renting the whole house, and will most likely be collecting the rent from the parents. Just be sure to enforce absolutely no parties or damaging the house or you will collect hefty fines.
Also, if you're not any good with fixing stuff, you could find a handy guy to partner up with. You would supply the capital to purchase the property, and he would fix it up, for a percentage of equity in the property. So if the house cost $18,000 and the amount of repairs was equal to $18,000 (if you hired someone to fix it), then you both would get 50% equity. Meaning you both would get half of the rent and half of the cash if you ever had to sell. This could also work the other way around: you fix it up and the other guy supplies the cash.
The whole purpose is to leverage. Create value where there previously was none. Get your money and other people to work for you. Work smarter, not harder.