To become good at poker you have to REALLY want to succeed because you are going to have to put in alot of time to work on and improve your game. One of the absolute best things you can do for your game is to find/create a group of yourself and few people and study poker at LEAST once, if not twice a week.
After i had the basics down i did TONS of research from all the resources of free content i get ahold of. I read plenty of books and watched tons of concept videos, posted hands on here for review, etc. and eventually what happened was i absorbed all of the content i could and basically reached a standstill with my game as a whole. I joined a study group which i immediately loved and it was surely helpful. I knew I played well, but I also recognized my results were not where i wanted them to be. Recognizing this reality was immensely helpful, and though i played decently on some level back then, I was nowhere near as good of a player then as i am now. How did I achieve that? Well, for me personally, the BEST thing i ever did for my game hands down, bar none - was to get coaching.
The reality for grinders, both MTT and Cash alike, is that as we move up, skill sets in the general population improve and so there comes a time where if we are going to succeed at higher levels - we are going to need insight from those who are already beating those levels and in reality that information just doesn't come free. Coaching focuses on you as an individual and the mistakes you are making as a player, it tailors to you specifically rather than being part of a mass content training site -- not that they don't work, because on many levels they certainly do, but nothing compares to content solely focused on you personally.
As a whole, i would say for most micro games and even a lot of mid level MTTs and such that the available free content and the 30 day course here on CC are viable resources to get you playing well enough to beat these games -- the harsh reality is that as we move up in stakes -- there are more players putting in more work, studying VERY hard and working with tons of tools multiple days a week to obtain and keep an edge in their fields. Beating those games will require the same amount of understanding and game dedication for us to become profitable at higher stakes. I cannot speak for cash levels, but i believe a lot of MTT games $22 and higher are where we start seeing a decent few regs out there CRUSHING these games and without being on their level, its just going to be much harder for us to find the victory vs that edge of the field.
Hope this makes sense, and i hope this helps!