So I'm starting to main Sage I've practically breathed it for the past 3 days, but I seem to have hit a wall (pun yes absolutely intended). I have seen around 6 videos in the past few days on how to place in different maps the different wall, but though that does somewhat help, I have trouble deciding when is a good Idea, sometimes I use it to early sometimes too late, the most recent one mistake was to block of a part of Lotus in which there was already smokes ahead, so I got flamed by my brother, so I'm looking for advice on how to decide, what should I prioritize what can I do to improve my judgement with this skill that can make or break a round. I don't want no-nos I want the way you guys come up with the answer, how do you weigh the pros and cons, of course absolute nono's like the smokes one are welcome but like other than that I think it's not going to stick that much to my mind. Anyways thanks for the help I appreciate it!

PS: I have a tournament on Saturday (Two days after this post) and I'm suppose to be somewhat proficient with this skill, really proficient.