One of the biggest challenges I have faced in my attempts to get more illustration work is finding balance between teaching, administrative responsibilities, and my art. I find spending time on building my illustration business the first thing to go, because the other aspects of my job are more pressing. I have many roles and the demands for those are increasing without the release of any other responsibilities. 
As such, I needed to do some serious reflection and make some decisions on how to accomplish my desire to get more illustration work. 
First, I applied for a sabbatical. This removed the administrative responsibilities that were so overwhelming and many of my other work demands. It allowed me to focus on illustrating.
Second, as an illustrator, I need to balance my time between creating and marketing. I have a tendency to focus more on the art work and hope that people will find me. Although this approach had brought in a small amount of work over the years, my-self-promotion efforts needed to increase and be more purposeful.
This involved planning. I now plan out my weeks. When will I work on illustration, and when will I work on contacting potential clients and other self-promotion efforts? Daily, I look over my plan and make adjustments based on what has come up. This has helped immensely in progressing toward more illustration work. I still have a great deal of work to do, but I am making progress. 
An example of a weeks planning
I realize this approach is not for everyone, but it has helped me. Some form of organization and planning is needed. I offer this as one solution and it is evolving and changing as I continue to work.
Now I am in the process of being patient until I see the results of my efforts over the last year or so. I will share my sure fire way to develop patience in two weeks.