you could try doing things for many different companies on the web, there are lots of forums were people are looking for someone to do various things for them. Some pay well some don't but if there use your work then thats more stuff for you to put in your portfolio. Even if they don't use your work it can still go into your portfolio. I would say everytime you have an idea do something for it, the most stuff you can show the better. Guess it depends if you want to do something local or anywhere (the web is good for that).