If a toyota camry won' t start but makes a clicking noise, what needs to be checked?

If Your Toyota Camry won't start, but makes a clicking noise when You turn the key in the ignition, then Your issue is almost certainly Your battery. This is especially true if it will only turn over once or twice the first time You try it. If You have the capability, test Your battery. Make sure it's holding a sufficient charge. If it's not, then You'll likely have to replace it. Unfortunately, this might not be Your only issue. A component might be drawing power, or You might have a faulty alternator. There's a number of things that could be Your issue, but the simplest is just an old battery that no longer holds the charge it needs. Cross Your fingers that its the latter.