Smooth the air bubbles out of the condom as you unroll it. Make sure the condom is fully unrolled. Use only water based lubricant with latex condoms. Never, ever use an oil based lube or product with a latex condom. Heterosexual couples who would like to increase their protection from sexually transmitted diseases and pregnancy, should also use a spermicide with the condom.
Contraceptive foam is especially effective.
After ejaculation, hold the base of the condom and withdraw the penis before it becomes soft again. Otherwise you run the risk of the condom coming off. And the last thing you want is for it to get stuck somewhere. Be very careful with fingernails and teeth around condoms. Don't get carried away and rip holes in it.