Apply soapy water where you smell leaks and watch for bubbles. If you see bubbles, don't attempt to fix the leak yourself. The best and safest way is to call your gas company to come to your home. They are professionals.
The safest way would be to call in a professional or someone from the city you live in that has experience in this area. Not that you couldn't do it yourself. But gas leaks are dangerous and should only be checked for by professionals to make sure no one is injured.