Arrival/Departing Cardiff is rather simple with excellent landmarks though just watch out for the TV masts if its a bit hazy. Just a few notes that I remember from learning to fly and being based at Cardiff for a number of years.
You will almost certainly have a crosswind. Usually from the left on R30. If arriving from the north via St Hilary the chimney stacks are a good aiming point wit the airport to the left.
If you have a south westerly wind and using R30 expect some turbulence when flying over the cliffs on short final. You'll probably feel some sink there too. I used to stay a bit higher on approach to avoid this. Probably a good idea to stay a bit higher in case your donkey quits. The Bristol Channel isn't that warm.
If on R12 with an Easterly to North Easterly you may find a bit of a change of wind as its being affected by the BA maintenance "shed".
Looks like they now use in/out taxiways since I learned to fly there (we used to use Hotel for in/out on R30 and Golf for R12 unless you missed Golf!). On R30 expect to vacate Golf and departure via Hotel. On R12 its the other way around.
Unfortunately I won't be able to make it to this fly-in. Perhaps the next one.
Don't be daunted, ATC are extremely helpful and welcoming and it was a delight to fly from Cardiff. Lovely airfield.
Barry Island (*if* you really must!) not too far in a taxi (you over fly Barry Island if on a wide right base to R30).