While gas stoves produce the most even heat for cooking, they can be so frustrating when they just will not ignite. Certainly if it is releasing gas, you can still ignite it with a match, but your stove is designed to work on command. Not lightning means that there is something wrong with your stove that needs to be addressed.
It may be a gas stove, but it uses electricity to spark the flame. It is crucial that your stove has electricity to actually ignite using the spark feature. You will want to check the electrical outlet, if using a plug. If your stove is hardwired, you will want to check the circuit breaker. As it is a gas-using stove, often if the breaker trips, you may not notice it until you next need to ignite the gas since it plays such a small, but important role.
If you recently had a pot over-boil or some other large influx of moisture, you will want to let your gas stove dry out for awhile. Nothing dangerous will happen, but moisture will cause the spark to fail, making it very difficult to ignite the stove.
You will also find that moisture may cause an already ignited stove to start clicking even though the flame is already on. You will want to disconnect the stove from the electricity, purely to stop the clicking sound, and let it dry before plugging it back in.
This is a common one. You wipe down your stove, but that motion pushes food particles and grease into the small holes on the burner head. This clogs them, preventing gas from actually being properly distributed. This makes it difficult for the burner to light even if the gas line is clear and the gas is actually still being released. Check the holes and clean them as necessary.