One thing that I have found that works really well for most small businesses is to develop a good relationship with a great bookkeeper and have him keep you up to date throughout the year. Even if it seems like you don't have that many transactions each month, it pays to have your bookkeeper do this for several reasons.
First, you won't miss anything. The sooner it gets recorded, the less potential for loss of information like lost receipts. Also, you remember the transaction clearly and are able to explain it properly to your bookkeeper. There is no worse headache than at the end of the year trying to figure out just what happened in January.
Next, you will find more deductions. Doing your bookkeeping throughout the year instead of at the end of the year helps you to find things that you never would have thought of later. This helps you get in a better tax situation, and who doesn't want to pay less tax at the end of the year.
Another reason to do your bookkeeping "as you go" is the relationship you get with your bookkeeper. If he/she is a good one and you have a great relationship with him/her, they will look out for you and help you find a different way of approaching the oncoming taxes. There are always more than one way to do things and your bookkeeper is your key to this door of possibility.
Finally, and probably the most important reason is that you will know where you are at "as you go" instead of at the end of the year. As a business owner you should never have to ask the question at the end of the year, "How did I do?". You should already know because you have been keeping track. You should not be surprised by the tax bill at the end of the year because you already planned on it.