The reason
First you need to find a good Reason for learning foreign language,
because good Reason is making you motivated for learning and keeps your enthusiasm
at high level. The Reason could be anything and I'm not going to make examples because
if you can't find a good reason to start learning foreign language, then, maybe, just maybe,
you shouldn't even begin. But if you already have an excellent Reason, keep reading!
Go to a language school or learning at home?
Well, most people I know go to language school.
But that does not mean that you have to go too. People which are not
motivated usually choose language school. If your boss wants you to learn, let's say, French,
he'll send you to school - and if your boss want you to learn French, your motivation is zero.
And in language school, like in any other school, they make you do things (homework!).
But at home you learn at your own pace, at time which you choose. You have freedom to
learn in a way that most suits you and your Reason.