Landlording is simple. You do what you can to find the best possible tenants. Then when you have good tenants, you do what you have to do keep them there.
How do you find great tenants? Offer a great product, and screen your applicants.
What is a great product? One that is priced 3-5% below market in a good location in a decent neighborhood, that is spotless and in perfect condition, with small upgrades that don't make prospective tenants feel like you picked the cheapest thing on the bottom shelf of Home Depot at every opportunity.
After that, things get murkier, because now you get into market segmentation.
If your product is a studio apartment in NYC, you need to be adding stuff that will appeal to the kind of person who is going to be looking for that. Someone who is sick of roommates and making just enough money to get rid of them, but not doing well enough to have a proper grown up apartment. So you put yourself in their shoes and say, "how do I make this studio apartment feel less like a tiny box?" Maybe it's updated light fixtures, or a great storage cabinet from Ikea that makes up for the small size, or something like that.
If your product is a 3/2 SFH in Corpus Christi, who is going to be looking at it? Probably younger couples, maybe with kids or dreaming of having kids. In that case, kitchens and baths make a big difference. You don't have to have granite to make them stand out. Make them spotless (hire maids). Upgrade the cabinet hardware. Add a nice tile backsplash. Upgrade the kitchen and bath faucets. Make sure the floors are gleaming and the paint colors are on trend. Make sure the rooms are brightly lit, not dim. Make sure the yard looks gorgeous, without spending a ton on landscaping. You want the kind of small touches that make people feel like it's just a little bit nicer than everything else they've been looking at and is a great value.
Once you have the place dialed in, spend a few hundred dollars getting professional photos taken. You can reuse them every time you need to list the place, and since almost everyone is shopping for places online, photo quality counts. No, you cannot get as good results as a pro using your phone or point and shoot. You need a real DSLR, real lighting, real lenses, and lots of experience.