I used to be a middlingly serious runner and my advice would be to find places that you like to run and then run in those places as often as you can. Start out running shorter routes, then build up the distance and the speed will follow.
Lots of people go for things like hill sprints or intervals, which I guess have their place but if you don’t enjoy doing them, I wouldn’t bother. I used to do hill sprints because I enjoyed them, but hated intervals so I didn’t do them. I’ve spoken to a lot of people, most of them much better runners than I ever was, who have told me that though they did fartleks, intervals, whatever, they found that simply building up to doing more miles a week was the thing that made a big difference.
I happen to enjoy running uphill off-road, and I’m lucky enough to live somewhere where there’s plenty of that on my doorstep. If it wasn’t for that, I’d never put on my running shoes.