How do you stop engine oil burn?

Worn out piston rings [or the cylinders themselves] and valve seating are the typical culprits. You can use a heavier weight oil, 20W50 for instance, to try and slow the amount of oil consumed, but that carries its own set of potential problems. There are also oil additives that purport to solve or slow the problem, but they cost more money and are short term, band-aid solutions at best and nearly fraud at worst. There is no way to stop the burning short of at least a partial engine rebuild. If you are lucky, the valve seats are the problem and requires only that the head(s) be rebuilt.