Thought I'd compile this from my previous bad experiences with renting!
1. When choosing a property to rent, ask your agent if they have rented for this landlord before and if they have had any previous complaints/disputes whether they were initiated by the landlord or tenants, its good to get an idea.
2. Keep a good relationship with your agent, once you find one you like! Use them every time you move and send other people their way. It'll build loyalty and they'll be more likely to want to place you with good landlords. They can also be a big help if you ever need a mediator or have any questions about bills or your rental etc.
3. ALWAYS DO AN INVENTORY! Do this ASAP when moving in, if the landlord hasn't initiated one or mentioned it within the first month then keep on at them until it's done. Go through it, sign it and make sure you're agreed on what is and what isn't in the property and the condition of everything (pots and pans, walls etc)
4. Take pictures. If the walls are scuffed, any dents or damage in the tables, the pots are stained, get it all on camera and either email it to your landlord or print them and have them sign them. You don't want to be held responsible for this once it comes to moving time!
5. Get receipts for everything. Every month when you pay rent, anything you have to pay for repairs wise (locks changed etc) as somethings are not your responsibility.
6. Even if it's not in your contract to pay for cleaning when you move out, do it anyway. A maid usually cost 30 odd for a good clean and get a proper dated/headed receipt for this. Then if the landlord tries to charge you extra for cleaning you have proof that you left it in good condition.
6. Before you move out meet at the apartment with the landlord to again go through the inventory. Go through the property. Give them the chance to point out anything they're not happy with and discuss and agree on who should pay (don't be bullied though). Make them sign a document on whatever they agree. Make them sign that they're happy with the inventory and the state of the place and wont ask for any additional money other than pending electricity or water bills, and have your agent witness this.
7. Keep on top of bills. At our last place we paid 100 a month but never actually received a copy of any bills during the entire year and were never told that we were going significantly over. Once we moved out it turned out we'd been using quite a bit more and were hit with an additional 750 bill. Hard to pay in one go, but if we had known that from month one we could have either given him a little more each month or looked at what we were doing wrong to cost that much!
Do you have any handy tips to add?