What a strat and a build order and copying pros gameplay will only get you so far. Your strat will only ever let you beat someone up to less than your skill with a worse build.
IF you want to actualy win you have to train yourself to pick up the skill to improve in every little aspect. This includes being able to anticipate every action your opponent is going to make and to simply beat him to it.
Improving in Warcraft III is really only an increase in the seed of your actions, so just play like 10 games a day or more. When you aren't playing you are thinking about Warcraft III. Look at what other people are doing, watch replays of you LOSING and realize what mistakes you made, and what they did that bested you. Make sure you are able to control emotions either. Getting frustaed or angry at losses is bad, getting excited during a fight can lead to mistakes etc.