Maintaining a hedgetrimmer is not particularly difficult and I am going to give you a few tips on effective ways to do it.
Cleaning the outside of the machine daily helps make sure nothing goes too bad inside and can prevent possible issues. Make sure the throttle lock and throttle function correctly. Make sure that the stop switch is working properly. Make sure the blades don't move around at all while idle. Regularly clean or replace the air filter to ensure it works properly. Check the handguard for damage and replace as necessary. Make sure all nuts and screws are tight and very importantly ensure there are no fuel leaks.
Every so often Jobs
It never hurts to check the starter cord and return spring. You can also check the vibration damping elements are working fine if it gets worse while using it. Clean or replace the spark plug. Fill the gearbox with grease. You should do this around about every 20 hours its been used. Check on the bolts holding the blades together.
Rarely necessary but Helpful
Clean the fuel tank, fuel filter, carburetor, fan wheel and fuel pipe. Replace any areas as necessary. Check all cables and connections, clutch, clutch springs and clutch drum.
Make sure you disconnect the spark plugs and battery cables and always wear safety glasses and gloves to protect from harmful chemicals and debris.