What are the most important accounting issues for a small business to consider?

maintaining adequate cash flow

There's plenty of different matters to sort through, but here's a start....
How to get your tax obligations in order - https://www.fullstack.com.au/understanding-your-accounting-obligations/
Getting the corporate structure right - https://www.fullstack.com.au/should-you-choose-a-trust-or-a-company/
Managing your cashflow effectively - https://www.fullstack.com.au/7-steps-to-managing-cash-flow-better/
 

Reconciling services / products provided with cash received 
Choosing the right software 
Managing cash flow 
Managing accounts payable 
Forecasting sales for the month and year ahead 
Sitting down with your adviser on a regular basis to go over the numbers and make sure the business is tracking to forecast/business plan