To begin, I would recommend checking out https://www.warzone.com/Forum/427054-maximize-intel-before-t1
to fully understand (if you don't already) pick and move order. Secondly, calculate your moves as much as possible. You should know at least half of your opponent's picks T1 and know the move order around 1/3 of the time and thus be able to fully know your opponent's potential stack/income for the first few turns. Once you get to the point where you can beat everyone under level 50 who is not an alt, join some se tourneys and watch the games of top players, and learn things like advanced tactics and positional play from there.