A very low flame is usually indicative that there is a leak. If this happens, sometimes it takes a simple adjustment like tightening the fittings. Always refer to the owner's manual that came with your grill for information on fixing leaks. Or, in the case of some less expensive or older models, it may be necessary to start the gas and then light a match. But either way it's pretty easy.
Some grills have a built-in temperature gauge.
If you're not lucky enough to have a temperature gauge, just light your grill and cover it for about 8 to 10 minutes . Don't be stupid a try to keep your hand there for 3 seconds, even if your hand is on fire. For hibachis , simply follow the instructions for a charcoal grill. Only use less charcoal . For electric grills , plug it in and turn it on.