If 22 being used....
Fly downwind aiming just outside of the large house on the hill at the end of downwind leg, but don't overfly that house or people get upset. Look for the road heading straight towards Welshpool town; that's the best place to turn base. Start your descent immediately; you are at 1500 ft remember. On final, as has been said, remember there may be high trucks on the main road on the undershoot. If the wind is at all strong, there will probably be a bit of turbulence; you're surrounded by hills. Don't panic; the runway isn't that short (around 800m) but definitely aim for the numbers. A go-around first time will probably get you used to how it all works, if necessary.
If 04 being used...
Can't remember any visual features for turning base, but don't turn too early as it's a long way down from 1500 ft. The house on final (the owner's house; you can overfly it) tends to cause a bit of windsheer and you'll probably drop 50 ft or so. Otherwise slightly easier than 22 as no main roads etc. Don't be put off if aircraft waiting just to the side of your landing point, ready for take-off.
That's all I can think off; I learned to fly there a long time ago. It took me ages to learn to land, and after that I discovered that most other places were easier. But it's really not that bad; this is meant to be helpful, not put you off. If it's doing the latter, ignore it and go anyway.
