Most gerbils can become tame in a very short space of time with gentle regular handling. Gerbils are highly inquisitive and confident animals and rarely bite.
It is a good idea first of all just to get your gerbil used to your hand before attempting to lift it out of its cage. Try gently stroking the gerbil while it is in its cage and offering it pieces of food from your hand. It will soon realise that it has nothing to fear.
Next try placing your hand in the cage and letting the gerbil investigate, and step onto your hand, whilst keeping your hand still.
Once it is happy that there is nothing to fear, take off the top of the cage if possible or open the door of the cage, and gently scoop the gerbil up in both hands. Do not hold it too tightly or squeeze it as this may frighten it. Do not pull or lift the gerbil up by the tail.
Don't lift your gerbil too high as if it jumps from your hands and falls it may injure itself. It is always best to handle your gerbil whilst you are sitting down so that if it does jump it does not have far to fall and will simply land in your lap.
A good way to get your gerbil used to you is just to let it sit in your lap and and let it investigate while you stroke it.
Once you have taken your gerbil out of the cage, and are sitting, face the gerbil towards you - they seem less inclined to jump if facing towards you. Let the gerbil walk from one hand to the other. If your gerbil does attempt to jump, let it and then simply pick it up again. It is better to do this than try and hold onto the gerbil which may cause it to become frightened. Once it is happy to step from one hand to another, gently start to curve your fingers around its body so that it can begin to get the feel of being held.
Before long your gerbil should be happy to walk from one hand to another with your fingers wrapped around its body and you can then start facing it away from you whilst you are sitting down and letting it walk again from one hand to another.
Some gerbils are more nervous than others and may take a little longer to become accustomed to being handled. Be patient and gentle and your gerbil should become very tame.
If your gerbil is really frightened or has had a bad experience being handled and bites whenever handled, try handling it whilst you wear a pair of gloves and handle it as indicated above. The wearing of gloves will help your confidence which in turn will help the gerbil. Once the gerbil stops biting you can move to handling the gerbil without gloves.
Younger children should be supervised when handling gerbils as they may unintentionally squeeze a gerbil, causing it to nip or injuring it.