Increasing run distance

that's how I tend to do it, although I think it depends on what distances you are doing. If your long run is 5k for example, I would do that 3 x/week and then slowly increase the distance of one of them. There is a school of thought that says you should do interval training for one session, a tempo run (shorter distance but faster than long run pace) and then a long run. That increases speed and stamina.

I can't get on with tempo runs though...

Don't increase your long run by more than 10% a week - otherwise you might overdo it.