Tax deductions are a very tricky business to get into. Obviously, if you are not a CPA, you might not be aware of the latest deductions that are out there. So the typical rule of thumb is, if it might be deductible, go ahead and save the receipt in your normal way of doing so. If all else fails, it may at least be a good revelation of where your money is ultimately going. But the best rule of thumb as far as determining what might be a deductible expense is, if you have got to spend money on it and you need it, it may very well be a deductible item for you.
The trick about tax deductions is in deciding what your actual needs are. Granted, taking a client out to lunch is a pretty good deduction. But taking your friends out for drinks, which could be “rebranded” (as in, lied about) as a deduction, has some issues about it. While you would be wise to deduct things such as your work wardrobe and your mileage, there are obviously some limits regarding what you actually need, in order to make sure that your business runs well. But where a lot of people make a mistake is in not remembering all that they have bought in the line of their business.
Everything counts, after all. While you might not consider spending a few dollars on a ream of paper and an ink cartridge to be significant enough to remember, that receipt is your ticket to either getting back or keeping some of the money that you worked so hard to get in the first place. While that money might not be the most important thing to you, it is going to be important if you end up owing on your taxes. So you might as well start being dutiful about it right this moment.