Why not use the methods of corporations? After all, employees are economic agents as well.
Increase your profit by reducing your costs:
Your costs are the hours you spend working. As your output (salary) won't increase in the short-term, it's logical to reduce costs by decreasing your input (hours spent working) to increase your personal profitability.
Increase prices by creating additional demand:
Talk to other employers by applying or setting up a LinkedIn profile. Do it during working hours. False advertising by having your work experience seem more sophisticated than it is, never hurt no one. Sell to the highest bidder.
Reduce competition among your peers to drive up prices:
Unionization and collective bargaining reduces the competition which in turn can increase prices, i.e. wages, by market forces. Corporations don't like market forces.
Exploit the commons:
Corporations love free stuff, from government support to using the natural environment. And you have access to their commons, e.g. paper, pens, mugs, coffee. Take home whatever you want. Use workplace tools for personal profit whenever possible. Feel bad about it? Your labor made their purchase possible in the first place.
Overestimate the time you need to complete a task:
This is similar to the first point but from a time management point of view. Your workload only grows when you finish your work early. So always overestimate the time needed and don't submit results until the end. Corporations like to overestimate the cost of products when it comes to negotiating. Your hours spent working are your costs so do not hesitate to overestimate.
Advertise all your achievements, bury mistakes:
Corporations love good PR campaigns. You can do PR as well. Never hesitate to talk about all the good stuff you achieved and how hard it was to get there. Even if it's not true. Blame mistakes on circumstance. Straight out the corporate playbook.
Collect data and information on your employer:
Corporations won't hesitate to record anything you would do and use it against you when push comes to shove. You can do the same. Maybe you witnessed some shady activities. Collect the evidence. If you're somehow involved, make sure there's a paper trail. If there's no paper trail yet, write an E-Mail which at the same time might help exculpate you. You might need the evidence some day.
Know-how transfer:
Employers like to take advantage of your work experience. They use knowledge management to make know-how independent from individuals. Use those tools and knowledge bases, extract any know-how you can before you put in your notice. Use the know-how you have access to as a resource for your personal profit – just like your employer did with your know-how.
(Use with caution. Not everything may be be feasible for you.)
Expand the list in the comments.