Use a prewax cleaner on the car. It will remove oxidation, wax build up,etc. I use it on every car I have. It shoud be done every 6 mo. to 1 year depending on the exposure to the ellements. It brightens up the finish like nothing else. It's not a compound. It chemically cleans the finish rather than mechanically. There are many brands of it on the market.It is often referred to as step one.A very important one at that.
You may need to ultra fine compound your car maybe? Just remember the word ULTRA FINE.