If you need a help about learning when to level-off during a climb just remember the 10 rules. If you are climbing to 10.000 ft and you rate of climb is 1.000 ft/minute just use this formula:

rate of climb / 10 => 1.000(ft/min)/10= 100 ft

This means you will have to start to level-off at 10.000ft-100ft= 9.900 ft

Suppose you are in a rocket and you have a rate of climb 6.000 ft/minute that means the result will be

rate of climb / 10 => 6.000(ft/min)/10= 600 ft

Level-off ? 10.000ft-600 ft= 9.400 ft