When chosing the freelance path, no matter the geography or industry I doubt your main driver was to get lots of money short term (ok, maybe for some this could be true). The usual reasons are: seek of personal freedom, independence, need of self organization, sometimes even a seek for recognition you were not getting in a "corporate" world.
I'm not going to tackle now the dilema, so popular in the coaching industry, of technical worker versus enterpreneur (if you want to know more about this just type "e-myth" in google).
Back on track: If you are not doing bad, you are probably at a point when you are getting a decent amount of revenue based on the amount of work that you can handle.
There is the entrepreneurial path if you want to increase the amount of revenue (basically creating an organization that will per se generate revenue, based on your ideas and based on the fact that you will be able to sell your service higher than it costs you to generate it).
But aren't there other paths to follow if you want to increase your revenue? I believe there are.
Stop selling hours, stop selling words (if you are a translator) and start selling value. For your clients, value is that indefined, hard to perceive feeling that they are getting much more than they are paying for.
We all believe we are the best at what we are doing. Reality is (I know you know :-) ) that there is someone somewhere that is probably better than you are...(similar to the reality that there will always be someone cheaper). But still, it may be that your clients care about something very specific that will make them feel at ease when working with you.
Identify that need, try to make it as specific as possible and build your identity around that. By making this analysis you may realize that we are not all exactly the same, that your specific niche values a certain characteristic much more than another. The important switch comes here: do not use this to get more work...but concentrate on using your specificity to market the kind of clients that are willing to pay that little extra to get what you do best (that value).
Let's put a simple, not very ellaborated example: Consider you charge 15% more on urgent jobs. What would happen if all your jobs are considered as urgent by clients but you manage to organize yourself in a way that delivering urgent jobs does not mean you have to work in urgent mode?
I'm sure that adding value, looking for the right niche and right costumer is the strategy to follow.