Most incidents aren't sophisticated
Many common attacks begin with ordinary weaknesses: a reused password, a convincing phishing email, access that was never removed, or software that was never updated. Federal small-business guidance consistently prioritizes those basics because improving them reduces risk even when a company has limited time and budget. The goal is not perfect security; it is to remove easy paths into the business.
The fundamentals worth doing first
Set up email authentication (SPF, DKIM, and DMARC) to make domain spoofing harder. Use a password manager and unique passwords instead of variations on the same one. Turn on multi-factor authentication wherever it is offered, prioritizing email, domain registrar, hosting, and administrator accounts. Keep working backups of anything you cannot afford to lose and test that they restore. Remove access for anyone who no longer needs it, on a schedule rather than only when you remember.
Many of these steps are low-cost, but they still require ownership and follow-through. Assign someone to review access, updates, backups, and recovery information periodically so the controls keep working after the initial setup.
What this looks like in practice
A common application-security failure is hiding a page in the interface without enforcing the same permission on the server. Someone who knows or guesses the route may still reach data or actions they should not have. That is why a review should test access controls directly instead of assuming the navigation proves they work. Small-business security is usually a short list of controls, applied consistently and checked in practice.