Check for gas leaks before you do anything. Ensure that the lines are connected perfectly to and from the range. Check the quality of the hose and carefully inspect it for holes. If you find any breach, continue troubleshooting only after you’ve replaced the gas line.
Check the source of gas. If you get gas from natural gas piping, check the switch on the pipeline leading to the range. If you get gas from a propane tank, ensure that the tank is not closed.
Lift the cap off of each burner on the range. Clean the caps with a range cleaning solution. Dry them before you put them back on the burners. This is especially if you're not getting get a flame or the flame is smaller than usual.
Open your windows to improve the flow of oxygen if you get an orange flame. The stove should have proper air intake to release a blue flame that won’t leave soot everywhere.
Move any cold propane tanks to a warm environment if you have problems starting the range. The tanks might have cooled beyond the ability to effectively release gas. If you want to warm the tank quickly, place it in moderately warm water.