WAITER - Breakfast, lunch, and dinner, people have to eat. One of the most flexible jobs as far as hours go, and also it is usually easy to exchange shifts with another waiter. Apply at places around the theatre district, as these restaurants tend to be more sympathetic towards an actor's schedule.

BARTENDER - Usually pays a little more than a waiter. These jobs are a bit harder to get, as most bartenders make too much money to quit, so there are usually fewer openings. A bartending class is essential if you don't know how to make the most popular drinks.
EMPLOYMENT OPPORTUNITIES

OFFICE TEMP - Like waiters, office temp schedules are often very flexible. In New York City, they are round the clock, as in late shift, night shift, etc. Of course you will need some basic office skills, such as adequate typing speed (over 50-65 wpm), basic computer software knowledge, and you must be polite enough to handle the phones, etc.
EMPLOYMENT OPPORTUNITIES

PROOFREADER - Very flexible and you can do this in your own apartment when you want to. Again, you will need some basic skills. There are proofreading classes available.
EMPLOYMENT OPPORTUNITIES

DOG WALKER - This would be a great start-up business for yourself - please LOVE pets if you choose this route. Merely tolerating pets isn't enough to grow this kind of business.
EMPLOYMENT OPPORTUNITIES

PERSONAL ASSISTANT - This usually entails opening mail, sorting mail, running errands, and simple secretarial skills. A wonderful flexible job when working for the right person.

BE ENTREPRENEURIAL - I am a big advocate of starting your own business. You have skills? Swimming? Think about a job as a life guard. Knit, sew or crochet? Get some samples together and go to little shops around the city to sell. Can you make dog coats or harnesses? Are you a great handyman? Are you a painter? You get the idea.