1. Pick an area. Say Falkirk for example.
2. Research that area like anything. Be able to know from looking at a listing if it is a deal or not.
3. Visit every estate agent in town like you are a big shot. Let it slip into the conversation that you have cash to spend. Tell them you are only interested in REAL deals, i.e. 15% below market or more.
4. The first time any agents call you make sure to give them it hard telling them that the deal they have offered you is shit and not to waste your time again unless they have something special.
5. Eventually you will get a deal from some desperado. This may take 6 months or so but don't worry. It'll happen. It is nature.
6. Once that deal is going through make sure you call all the other Estate Agents telling them it was you who bought XXX Main Street and that you want more.
7. This will show the others you mean business and you will get more deals that year.
8. When you buy the property just hand the keys back to the agent and tell him to rent it out for you. They will have been saying for ages how great it is so make them show it. They will have a little more skin in the game than a third party.
Obviously there is a limit to how many really good deals you can get in a town. There is only so many desperadoes who will sell cheaply, however in a town like Falkirk I'd say you could get 4 a year. That's how many you'd get in Corby (61,000 population) and Falkirk is much bigger (156,000 when you count Grangemouth, Boness and Larbert).
Price is key. I wouldn't worry too much about décor or anything like that. Also I'd stick to the bottom end of the market. The Rental game is like a pyramid. Loads of folk looking for 1 beds, a bit less looking for 2 beds, much fewer looking for 3 beds and hardly any looking for 4 beds and I'd be surprised if a 5 bed rental market even existed in Scotland.