In order to run a successful business, it is imperative that you have as little accounting errors as possible. This takes a little work, but with the right methods, you should be able to reduce your errors.
Firstly, if you have the facility to allow software to raise all of your invoices for you, you should definitely use that method as opposed to raising manual invoices. Manual invoices leave room for human error, therefore increasing the risk of accounting errors. You should also try to import all of your invoices into your accounts package, rather than retype all of the information in yourself.
Again, typing and manual entry leaves room for human error. You should also use credit limits and stopping methods to stop customers that are unable to pay using your services. With accounts, automation is really helpful, and is less likely to cause any problems, so wherever possible, you should utilise it.