The biggest problem is people don't keep good records. If people kept better records, they'd save money.

Make all you can, save all you can, give all you can

The biggest mistake regarding record-keeping is not writing things down or not remembering where you wrote it down.

Your guess is as good as mine.

My biggest problem is retaining the exact information.

Lower taxes are great, but if its going to cost you money, it's not worth it. If a stock hits your sell range after 3 months, do you really want to risk 9 more months of fluctuation to get a lower tax rate?