Although not even the world's best coach would be capable of providing a written list that could guarantee success, the following 10 points are core things to remember when attempting a perfect freestyle stroke (also known as the crawl).
With luck and perhaps a little poolside advice from another swimmer or instructor, these 10 items should ensure that you have the basic freestyle stroke mechanics down pat. You may already have several of them mastered, or you may just be starting to learn how to swim. Either way, there's no better time to make technical improvements than now.
Take one tip per week and only concentrate on that specific aspect of your stroke. The next week, choose to work on another tip, but remember the one you practiced the week prior. In 10 weeks time, not only should your stroke be markedly improved, but the improvements will feel natural and require less concentration because you added them together slowly over the course of a few months.
Rather than information-overloading yourself with too many things all at once (a common problem at weekend-long swim clinics), you will have taken several months to carefully master all the different, basic elements.