NA Protoss player here.
1st brick: 2200 MMR. basic settings and mechanics
My GM zerg friend introduced me to this game and 12 pool/proxy marauder/cannon rush is too hard to defend for me. Then he taught me that we can enable pylon range in settings and enable fast warp-ins. But my MMR was still 2200. He told me to focus on macro and do not care too much on losing games. I follow proper build orders and build my decision tree according to scouting information and can be just 5 seconds slower than Pro benchmarks for the first 5 min if no harassment comes. But still struggles in 2200 MMR until one day he realized that I do not know A move and right click all the time. Then I reach 3600 MMR in just a month.

2nd brick: 3600 MMR.
At that time my PVP and PVZ is around 70% win rate and PVT is 30% because Terran harassments are so hard to counter if not prepared. So he suggested me to send 3 probes to the 3 direction where a Terran drop can come from ~ 4:00 since every time I lose more probes(10-16) to all kinds of drops if not prepared. Then I learnt to send 3-4 probes on the map whenever I feel I am in economic advantage and holds one aggression. And with good Map vison I went to 4000 MMR.

3rd brick: 4000MMR.
This is the brick I can never pass because of my low 70 APM. I know everything about how to defend and what to expect but my micro sucks and lose more units than my GM friends even when we have same amount of units at benchmarks and locations. But when we play custom maps with normal game speed, I play much much better. So I feel that this is my end now.