As a software developer much of your time will be spent self-teaching ('ramping up' on various technologies). The more familiar and comfortable you are with that, the better off you'll be - so the biggest thing is to just sit down and do it. Write your first Hello World in a language, figure out the basic syntax, get familiar with it's objects, go through some tutorials. Once you've grasped the basics, you'll start to get used to what common tasks you'll use to learn a new language (e.g. file read/write and regex, database connections, etc.).
On a more personal note, the biggest thing about learning a language you're unfamiliar with will be motivation. If you've got a project (for school, work, an open-source application, etc.), that will typically provide that motivation; with self-learning, you'll have to come up with something that will keep you motivated.