I have started to implement this rule in my business efforts and I thought it would be applicable to writing a sales letter so I decided to post it.
*******
Doing activities that are productive are key to meeting your goals.
So, if you want to meet your goals in the least time possible, you should only do tasks where you can measure the results.
For instance, if you make changes to your sales letter, you should write down how much time you spend on a particular change and record your change in conversion rate (if there is one).
Then you should calculate how much this change means to you in dollars.
Once you analyze your various effort by how much money they put in your pocket for the amount of time you spend, you can focus all your efforts on the most profitable/productive areas.
Of course, the only way to focus on the most profitable tasks is to make sure that you can track and measure the results of everything you do. If you dont measure, then your effort could be worth a lot or a little, but you will never know unless you track it.