And because I am Mac based I use MYOB which was the only business softwear available for this platform way back in the 80's.
If I was doing the same thing now I would be looking at some of the freewear as MYOB has become way too bloated and two expensive for small business.
Most important is to make sure you paper system works before you put it on computer because all the computer will do with a badly set up system is to accelerate the downfall.
If you are going to try to work paperless then the magic word is backup, backup backup & backup.
Buy a carton of flash drives and label 7 of them with the days of the week ( a lot cheaper that way)
then 5 more marked W1 through to w5 ( weekly back ups )
and 12 more labled with months according to your financial year.
I did not do this an paid the price having to reconstruct a full year of trading on more than one occasion ( slow learner ).
I now run MYOB on a totally seperate computer, which is not connected to the web and has 2 internal hardives and 3 external hard drives set up as mirrors.
Only 1 of the external drives is ever connected to the computer at any 1 time thus the other 2 become the "last week" and "last month" active back up.
Because they are mirror drives, when any one is plugged in the computer will automatically update it in the background whie the computer is turned on.
Whatever you do, do not under any circumstances go with any "cloud" based system none of them are secure.
The other trick that I found works, is to never open any mail or write a cheque unless I am sitting in front of the computer, in fact the computer actually writes all my cheques.
I connect it to the web, download the emails, send orders and make cedit card payments then pull the plug and work off line.
While this might sound silly it ensures that everything goes into the "box"and you are not chasing a missing item at the end of the month when accounts do not reconsile.
A customer who was a book keeper who showed me another trick which is to set up your company with all the accounts, then export them into another file which you work from.
At the end of the financial year, you export the account list again, add your current amounts as the opening balances the use this data file for current financial year.
Thus you can go back and fix up problems from last year without affecting this year.