The simplest answer is "Always" be looking for auditions. People are casting year round for film, though some areas are much busier than others. Currently many film schools are holding auditions, and film school projects are a great way to build up a reel which will lead to more jobs and possibly agency representation. Craigslist, acting and film production sites on Facebook are great places to check every single day to see if you fit a role someone is looking to cast.While acting may seem like a "part time" job to some, the business of being an actor never stops. Make it a habit to check any casting resources you can find in your area, and when you see that you fit something, submit a headshot and resume immediately. Just like any other job, people are eager to fill open positions and don't have a lot of time to wait. Good luck!