What advice can you give to someone who wants to study mathematics on his own?

I'm currently not a math major but I would like to study mathematics on the side. However, I don't know how to pursue it as a hobby. There are so many topics to study, it seems, that I can't systematically approach them to learn.

One way to narrow down the list of topics is to reflect on what I would like to learn and what interests me. What are some questions that I should consider?

Re: What advice can you give to someone who wants to study mathematics on his own?

At present I am using mathematics as a hobby. I do have good entry level maths behind me, or maybe a little better.

I have always been a very 'block' learner in the past but at the moment I am just having fun. I look at posts and sometimes join in and other times just look and learn. If I see something new and interesting i google it and then just follow where it takes me. I have found a lot of very good you tube clips and I know that there are a lot more out there. I am also very interested in teaching mathematics and I am finding new and better ways of doing 'old' things.

Of couse many of the posts are over my head but that's okay. I just hone in on the ones that are at my level. I am learning heaps and it is a lot of fun.