One of the ways in which you can improve the fortunes of a blues club significantly is by getting it (the club) a corporate sponsor.
The process for getting a corporate sponsor for a blues club is actually quite simple. It involves identifying the sorts of corporate entities that are likely to be interested in sponsoring this sort of club, and hitting them with proposals. Sometimes, having personal connections with the top folks at the corporate entities in question is likely to increase the probability of a successful sponsorship deal being hammered out.
A blues club is likely to get a corporate sponsor only if it has an appreciably huge number of members. In most cases, you also have to demonstrate how the corporate entity in question is likely to benefit by offering sponsorship to the blues club in question. A company that, for instance, specializes in the sale of good wireless headphones for running or one that specializes in the sale of headphones for all devices is likely to be interested in this sort of sponsorship deal. That is because the company would see it as an opportunity to promote its products.
All said and done, it is important to remember that getting a corporate sponsor for a blues club is a matter of chance. As such, there is a probability that you may not get such a sponsor, in spite of trying. You need to be ready to live with that reality.