From my experience, one of the best (and relatively easiest) ways to reach higher salary levels over a relatively small time frame is to, at some point, go to w

From my experience, one of the best (and relatively easiest) ways to reach higher salary levels over a relatively small time frame is to, at some point, go to work as a short term consultant through a consulting agency for a little while. If you have any decent skills, getting in will be no problem. The benefits of this approach is 2 fold; 1) you will obtain a broad and diverse set of skills due to traversing many different technology stacks and dealing with all sorts of issues. 2) As you move from client to client, the consulting agency which is responsible for placing you, will be ever-increasing the rate at which they charge the client for your work. Although you probably won't see any personal gain from this increase, the big benefit comes when a company wishes to hire you long term (assuming you want to be hired also) and it's time to negotiate salary. If you know what the consultancy has been charging the company for your work, you now have a huge advantage in your negotiations. Typically, they will charge the client 3-5x what they are paying you, so just as an example, if you make 75/hr, the client is probably being charged ~200/hr. I would think you could at least double your salary if not more during final negotiations with the company. This approach worked out pretty well for me, but it does assume you have some way of knowing what the client is being charged. In my case, I befriended a few people during my assignment which allowed me to open that door.