The shortest answer is doing.
A smooth sea never made a skillful mariner.
One boy is more trouble than a dozen girls.
Boys will be boys.
Two's a company, three's a crowd.
A burnt child dreads the fire.
We never know the worth of water till the well is dry.
Everyone must row with the oars he has.
God gives the milk but not the pail.
A joy that's shared is a joy made double.
Hope for the best, but prepare for the worst.
You may lead a horse to water but you can't make him drink.
He that seeks trouble always finds it.
Every path has its puddle.
Two wrongs can never make a right.
Danger and delight grow on one stalk.
Still waters run deep.
Many things are lost for want of asking.
One of these days is none of these days.
Time and tide wait for no man.