You know what would really help small businesses, like a lot? Public health insurance (covering things like vision and dental). A huge part of the cost of doing business is benefits for employees. Well, with public health insurance that's a huge budget item that suddenly small businesses don't have to pay.
Want to make it better? Expand social security to be something you could live off of. Boom, now you as a small business owner don't need benefits like 401ks. Your employees will be well taken care of by a government ran pension.
Want to go a step further? Expand public housing, public transport, and food security programs. Now all the sudden a business doesn't need to pay top dollar because the cost of living for everyone has been significantly decreased. You can easily find low wage workers and hire crews of them because the added income for everyone is more of a bonus rather than a necessity.
What else could you do? Reduce the full time work week from 40 hours to 30 hours. For a small business, it means you can actually focus on having your employees doing useful work rather than having them hang around an extra 10 hours a week doing nothing. For the employees, now they have spare time on their hands which means more opportunities to interact with the community and small businesses.
By taking care of the basic needs of the population you give the population a lot of spare capital and time. All of which can stimulate the economy to new heights.