For business spending I always use credit cards (cash for personal expenditure) as much as possible, and budget accordingly. A great way to earn points. I then file receipts away and keep spread sheets and hard copy records of both income and expenditure. I do my own books for 30 minutes a month, yet my accountant takes care of both the individual and company tax returns.
Whether or not you can do your own bookkeeping depends on your ability, I think. If you are sure you can manage on your own, then by all means, do it yourself. But if not, hiring a professional accountant could be a good idea.
Some popular software for accounting are QuickBooks, Reckon, MYOB, etc. Using a software is more convenient than paper since you can prepare a BAS report according to the form without difficulties.
My business is so small i have a book for spread sheet for income and a spread sheet for outgoings. At the end of the year i take one from the other and fingers crossed i'm still in the black. www.butterflyhostplants.cpm.au