Finding the cause of oil consumption isnt going to help the OP because it is irreversible, the only solution is to rebuild the whole engine. He is asking for a way to help it consume less. I correct myself i actually meant use 10w-40 which is thicker and therefore harder to burn through, just as an example drink a cup of water (5w-30) then drink a cup of honey (10w-40) you will see that the cup of honey takes much longer and is tougher to drink due to its thickness. While using this thicker oil make sure to warm the car up when cold since it does take longer for it to circulate throughout your engine.
The 2002 Toyota Corolla has a well earned reputation for consuming oil and out of all model years of Corolla's, the 2002 year was the worst one for this problem -
http://www.carcomplaints.com/Toyota/Corolla/
Finding the cause of the oil consumption most certainly will help and is many times reversible.
There are many potential causes of higher than normal oil consumption. Below I shall list a few -
1. Plugged PCV valve/system, increasing pressures inside the crankcase, which can force oil into the PCV system, where it is then sucked into the combustion chambers and burned.
2. The use of petroleum oils can many times cause sludge, carbon and varnish deposits inside the engine, which can cause the piston rings to become gummed-up, stick and not function properly, allowing excessive amounts of oil to get by the rings, up into the combustion chamber and be burned.
3. Petroleum oils have a much higher volatility rate, (burn off easier), than a top performing PAO synthetic oil does and lower performing petroleum oils can burn off/evaporate at a much higher rate than even a better quality petroloem oil will.
4. Higher mileage engines can tend to develop oil leaks, especially when using petroleum oils as this practice allows the engine to run hotter which dries out and cracks all manner of different gaskets with resulting oil leaks.
Using a thicker viscosity than what the engineers who designed the engine recommend will only serve to exacerbate all the above issues and will also reduce fuel economy, increase emissions, increase wear rates, reduce power/throttle response and can cause the engine to run even hotter as the thicker oil flows at a slower rate and doesn't transfer heat as well.