You could sit around and wait for inspiration to strike. (It happens sometimes.) But here is a more proactive approach you could take to increase your revenues. Feel free to employ any or all.

1. Conduct tiny experiments.

Your resources are limited and there is no guarantee that even the most brilliant marketing idea will work. That's why you want to hedge your bets, both by trying a number of ideas simultaneously and keeping the cost of each one low. 

2. Place your bets (quickly.)

No, you don't want to lose money.  But, since you are not risking much, you can afford to have some of your marketing experiments fail.  Get your product or service out there fast and let potential customers tell you if you are onto something.

3. Where do you experiment? 

Obviously, in areas where competitors don't exist, or are weak. (There is absolutely no reason to take on an entrenched competitor head-to-head.) Not so obviously, in places where you feel strong. The confidence will help you overcome the inevitable hurdles you will face.

4. Always look for low-hanging fruit (part I).

No customer wants to be entirely dependent on just one supplier, no matter who it is. Ask yourself, what your competitor's customers want. Better yet, ask them--and get yourself a new client.

5. Low-hanging fruit (part II).

It is far easier to build off an existing idea. Yes, it would be great to come up with something that has never existed before in any shape or form.  But if you do, you are going to spend an awful lot of time educating your market about what you have. There is a reason the cliché is "if you build a better mousetrap," and not "if you build a brand new, never been seen before mousetrap."

6. One step at a time. 

Speaking of creating that better mousetrap, be satisfied with making one significant improvement in a product or service. You're bound to make mistakes just attempting one thing--many more if you try to do too much.

7. Let the market do the work for you.

People will tell you what they like, and what they don't, about your product.  Incorporate their ideas with yours.  It's lovely that your favorite color is purple, but if customers--and potential customers--want your product in yellow, give it to them in yellow.

8. Import.

What marketing ideas are working in Modesto, California, that you can try in Marblehead, Massachusetts.  Get on a plane and take a look.

9. Think Small.

Keep looking for limited markets where you have a genuine competitive edge.

10. What is the competition doing right?

They have spent millions to create marketing programs that work.  What can you adapt and use as your own?

11.  Ask customers what they want... and give it to them.

There is no better marketing strategy than that.