If you hook up with a for-hire car parking service (the type hired out for fancy neighborhood parties) you can make some nice cash tips in just a few hours at night and on the weekend, when parties are held. The key here is to do a great job by showing hustle and being super friendly. This was one of the most enjoyable jobs I had during graduate school. Who doesn't like to drive nice cars?
Whether you have a website or are still dreaming up ideas for a blog, you can also look into affiliate marketing. With affiliate marketing, you partner with brands and businesses within the content of your website. If you mention a product or service, you link to that produce or service using a unique affiliate code you received when you signed up for that particular affiliate program. From there, you’ll make money any time someone buys a product or service through your link.