Get an eye pillow. You can get one in a new age book shop or pharmacy or health nutrition store. It is a small silk pillow about 7 cm by 15 cm long with some scented stuff inside.
When you are sitting somewhere for a while, and you will not need your hand, either hand, put your hand on the table or your leg if there is no table, and put the pillow over the back of you hand.
The exercise is to not move your hand for a period of time, as long as possible is best.
The pillow is just so you will be aware of your hand and know if you are moving it.
This practice will help develop the ability to focus your mind by training to keep your body still.
Meditation is a complete waste of time if you do not keep your whole body completely still with as straight a back as a statue of Buddha at the same time as being totally relaxed.
This is the reason for the lotus position or other positions that allow your back to be straight but relaxed. If you cannot sit in the lotus posture, then sit on a flat bottom chair, like a kitchen chair, with a book of about 5 cm under each back leg. This puts the seat on a downward slant. Sit halfway on the seat, do NOT try to get your back leaning on the backrest, your back must support itself naturally.
The spine should be like a stack of coins. Nothing restricts the coins, they stay piled straight because that is the law of gravity. They must be in a perfect column, or they will topple. Your spine must be the same, in line with gravity and nature without tension holding it up.
This puts your body in harmony with nature and allows your mind to be calm and clear because it no longer is distracted with a noisy body which is out of harmony and always fidgeting around.
This will help you start to learn how to keep your body still. You start with your hand to learn the principle, then you expand it to your entire body.