Practice, practice and practice.
Very few people can pick up a dowsing pendulum for the first time in their life (with no other dowsing experience) and get results. You have to practice, see what works for you, tune your pendulum to yourself and, finally, find your limits.
And that can only be done with lots of practice.  But that practice can be easy and fun and need only be a few minutes each day – or an hour or so a week. It is entirely up to you and what you feel happy with.

Some key requisites before you start to practice:
1. You must want to do it
2. You must have confidence in your ability to learn
3. There must be no strong negative influences around you (for example a sceptical partner laughing at you).
4. You must try to put personal worries, everyday concerns etc to the back of your mind
5. Before you start you must get everything you need prepared so you do not have to stop and break your concentration
6. Turn off your mobile phone or put it out of earshot. If it rings it will distract you.
7. Do not practice if you are tired or sleepy.

In the links to the posts below, I have put a series of exercises that you could follow in sequence. They will give you an insight into what / where / how you dowse as an individual.

• First step, your pendulum
• Second step, looking for a hidden object
• Third step, looking for water using a map
• Fourth step, yes / no questions