There is a lot of free help on the internet, so you can start with that. For instance, the ASL site will take you through the basics. You can find instructions for making signs for everyday words, such as 'mother' 'father' 'hot' 'cold' and so on - there are about 100 basic signs you can learn in this way. There are also online videos to make it easier.

You can also learn individual lessons. For instance, it's important to learn the alphabet in sign language, or fingerspelling as it's usually known, and this can also be done largely online.

Once you've picked up some basics, you should think about some lessons. There are a number of schools offering lessons - it's also a good idea to contact your local community or adult education centre, as signing lessons are sometimes free or at least subsidized. Finally, if you know any sign language speakers you should ask them for advice too.