I've had a variety of housing situations over the last 3 decades since leaving the nest. Dorms. Apartments. Trailers. Houses. Campers. A van down by the river (actually on the road sleeping in rest stops...don't tell Mom). Shared. Alone.
Lots and lots of experience with landlords and rentals and leases and sublets.
Here are some tips for those seeking a new rental:
1) Try to find a rental through a personal or professional connection if at all possible, but avoid renting directly from family or best friends. Some of my best rentals have been through a friend of a friend. Enough connection to make you both trust each other a bit and to not want to be jerks to avoid embarrassing the mutual friend. For example in grad school I once rented from an English professor who was the colleague of my professor's husband. Enough for the linking people to provide good references (though they may have regretted that after my dog at part of the door...sorry!), but not so much that either of us felt we were doing the other a favor.
2) Barring that, READ REVIEWS online about landlords and rental companies. My sister once called me up because her friend's daughter was moving to my area for grad school and trying to rent an apartment before arriving. She had gone through the WORST rental company in that town and was looking at apartments in frat row of a college town known for beer bashes that turn into 3 day riots. To me, this was NOT a place for a grad student serious about studying. I went to the agency to look at a few of the apartments on her behalf. 1 stank of urine. 1 just stank. All had mold. And the agency had draconian policies about renewing leases by January for the following August. Nevermind the pages long list of complaints with the Better Business Bureau and various other agencies and the easily located (thanks interwebs!) mass of lawsuits from former tenants. NO NO NO. I drove around and found apartments advertised only by yard signs in the better areas (not perfect..see "grad student' and add "budget"). I called one number and it turned out to be a professor retired from the department she would be attending. This is a good link as noted in #1. I viewed the apartments. And screened the landlord a bit. He was a decent human and we knew people in common (again, see #1). I sent photos, maps and reviews and she rented one of those. It seemed to work out well. Had she had the time to read the online reviews she would have known the rental company was a loser, and she didn't at that time have the gumption to call up the department secretary and ask about professors who have rentals (many aging professors having rentals...word). Being 1500 miles away put her at a huge disadvantage. Her mother, my sister and I were perhaps a wee bit pushy and controlling but it was for her own good.
3) Read the lease. All of it. Ask questions. Ask a lawyer or a friend with more rental experience if you don't understand something. This seems obvious to me but I hear that not everyone reads leases. There are terms that can really get you into trouble. Late fees, eviction fees, excessive notice for moving out, requirements to renew, etc etc etc. If you want to change something, both you AND the landlord/management company need to sign and date right next to the change to avoid either of you saying "I didn't know."
4) Keep a copy of the lease. Keep several. Scan it and email it yourself. This got me out of a sticky situation this very year. The property manager was frankly crap. Didn't answer calls. Took 6 weeks to return the signed lease and then it was just a cell phone photo of his signature, never a copy of the entire lease. Eventually rumor has it he delayed responding to an emergency repair call until a ceiling fell in. At last the management company and he parted ways. A new manager arrives on the scene and just assumes everyone has the same lease. Taking advantage of the crap nature of the previous manager, I had put many new clauses in the lease, like making it go month-to-month, lowering the deposit, and various other things. The dude never noticed but I was the only one who kept a copy of the least with the terms written in and a copy of the signature page with both his and my signatures, meaning that cell phone photo. So, the new manager just went with it. If your records are better than theirs, you win.
5) Take photos of the place as you move in recording every single detail. Again, email these to yourself and possibly the landlord. This records the condition at move in. There can be no debate. If your camera/phone/whatever had the option to put a date and time stamp on the photo, use it. Take pictures of every wall, floor, ceiling, window, fixture, appliance, closet and cupboard (doors and interiors). With digital photos this costs you pretty much nothing. As you move out, take the same set of photos with time stamps and email them to the same people as the first set. Of course if you're going to trash the place and just let the deposit go, don't bother with the photos unless you want to brag to your friends about your trashing skillz.
6) Re-read the lease every now and then. Boring, but you might find the landlord is not meeting the terms and that's always fun. Once every 6 months or year is fine.
7) View place before you rent if at all possible. If not you then a friend, acquaintance, or family member. If you've got no one to view it, go with the shortest term lease you can possibly get/afford. When you view it, do more than that. Smell it. Open all the cupboards and closets. Touch the carpet (if you can find a rental without carpet that is better...carpet is never quite clean and old stank will come back once that gallon of febreze the previous tenants used to cover the smell of beer vomit and cat pee wears off). If it is sticky just say no and move on, or if you can't, then make a note on the lease and get the landlord to initial it along with you. Check the water pressure and ask to see the hot water heater. Have the landlord show you the electrical panel. Is it old knob and tube wiring with screw in fuses? It might be OK but you may not be able to get much in the way of renters insurance if you admit it to the insurance company. If you don't have nice things, don't worry about it but get more smoke alarms. Open and close all doors. Flush the toilet. Turn on all faucets, hot and cold. Does the hot water show up quickly? Ever? Try all the electrical switches and if you're up to it, check the outlets. I always forget that last one and this last apartment ended up with a place with ZERO grounded outlets and many outlets that smoked or heated up. It was a month-to-month lease and cheap so I gutted it out...and added smoke alarms and fire extinguishers.
8) Make a note of everything. On paper, in email, where ever you like. Just write it down with a date. The date the first fuse/breaker blew. Because it may continue to be a pattern. The date the roof first leaked. The date the landlord showed up drunk and just stood there. Just make a note. If things go badly, you've got the record.
9) Be polite. No matter how gross the place or how drunk the landlord, you be polite.
10) Don't take any crap. Being polite does not mean being a doormat. Don't swear at anyone or threaten or slam doors in faces (unless someone is threatening, then all bets are off and call the cops immediately). Don't let the landlord come in without notice if notice is required in the lease. Do not allow the landlord to change the terms.
11) Print out or download a copy of the state, county and city rental laws. There is often a tenant-landlord office at colleges and universities where they have hard copies of these and their websites have links to the online versions. If you live in a college town, take advantage of that. If not, it's not hard to find. Libraries and city halls and county court houses are there to help you. I can't think of a state that doesn't have it's code online. The library can help you.
There are plenty more things, but these are the things I've screwed up or seen people screw up.