Substitute teaching shouldn't have to be a part-time job just to make some extra cash. Some of us who enjoy a flexible schedule still have bills to pay and would like to make a liveable income doing so. There's a lot than can be done to maximize your ability to make money as a substitute teacher, it just takes a little bit of thinking and a lot of strategy.
Work in Multiple Districts
Keep an eye on all of the local districts and have your substitute application packet ready. Apply at as many of the local districts as possible to ensure you'll have a stready stream of calls (and cash) throughout the school year. The more teachers there are, the more chance you have of getting called on any given day. If you're looking to become a permanent teacher it's best to focus on one district and take more jobs from them.
Work in Multiple Counties
This can be tough to do but if you're lucky enough to live on the border of two counties this can be the best thing you can do to maximize your earning potential. Typically, districts within the same county (if it's your everyday, average-sized county) will have the same days off. Holidays are usually standard throughout the US but the major breaks like Spring, Summer, and Winter can vary by several weeks. Currently, I work for two very small districts in neighboring counties and their Spring breaks fall on two different weeks. This means I'm making money from one district while the other is on vacation.
Be the Best
Being indespendsible to the school district is a surefire way to keep the jobs rolling in. Substitutes that are reliable (and available) tend to get called back often because teachers know they can get the job done. Teachers feel more at ease knowing that the curriculum is being carried out properly and the class is not missing out on a day of instruction and they are willing to pull some strings in order to have that sub back in the class the next time they're absent. Being the best will soon get you a steady stream of work and a regular paycheck.
Work in a Small District
This may seem a little counterintuitive but there is a definite strategy here that is overlooked by almost every substitute teacher. Most subs will apply at the largest districts thinking that there will be a surplus of jobs because there are so many schools. While this may sometimes be true, larger districts are well aware that they need massive coverage for hundreds of teachers. These districts tend to have hiring sprees and post vacancies online, getting thousands of resume submissions. They will often hire more subs than what is needed, leaving many with no work. Smaller districts usually avoid posting online because they have neither the time or the resources to leaf through thousands of applications. They also hire in smaller groups or will avoid hiring groups entirely, instead waiting for individual subs to roll their way. Working for multiple small districts can prove more fruitful than working for the largest district in the county.
Schools are everywhere so working locally should be no problem. Most districts usually only hire locals anyway so it would be to your advanatage to apply at the district next door. Living too far from a district can also limit the calls you get since the substitute administrator will call the closest subs first in an emergency. Living close by will also save you money in gas and you may even be able to walk to the school. You should also be aware that districts can pay drastically different. Districts usually pay depending on the length of the school day so if you're willing to drive make sure it's worth your while first.
Get Full Credentials
While this may cost more initially it will definitely open you up to more work such as long-term assignments (and long-term pay). You are more likely to get hired by districts since they are partial to subs with full credentials. Having additional expertise in a specific area such as special education or a single-subject credential can provide you with even more opportunities for work amd additional pay that is given only to those teachers with specific training.
Pick Your Days Carefully
I've never been opposed to taking half-days. Sometimes, I actually prefer shorter days especially if I have prior commitments. What's not smart is taking a half day if you live several miles away. Working for the sake of working is only going to cost you more in the long run. Remember, you have to burn gas and pay taxes so that $50 half-day comes out to $25 once you've paid your dues. Half-days are great if you're working another part-time job on the side or if you live minutes from the school. Half-days can also benefit you if you're trying to make your mark with the district, but be very careful and don't overextend yourself. Time is money, and this is no less true with substitute teaching.