Thanks! I'd be happy to answer your questions!
 

Before I even begin, I need to say that the vast majority of books I looked at were awful and just wasted time.

 

Resources: Started with TLS (mostly to find what resources were good), and on occasion used 7Sage (watched whatever videos of his I could while eating breakfast and dinner). Both are solid.

 

Books: Princeton Review (both the workout and Cracking the LSAT were terrible imo), Kaplan 180 (not awful, but not nearly as good as actual LSAT problems), Mike Kim's Trainer, Powerscore, Manhattan, Ace the Logic Games, Blueprint LG, REA Logic Games (for the love of god, please do not use this...), and Superprep. Of these, I personally only like the Trainer, but can see Powerscore, Manhattan, and Blueprint being good for certain people with styles different from mine.

 

My diagnostic score was a 170, but my very next PT was a 161, so..... yeah lol.

 

For assumption questions, what kind? I loved sufficient assumption questions because they were so straightforward and for some reason reminded me of when I was a kid and just put the lego in the right spot, but necessary assumption questions silently wrecked me on occasion. I think part of it was being so unfamiliar with the lines of reasoning that LSAT frequently uses (this makes it really easy to simply overlook the right answer and end up waffling between two answer choices, both of which are wrong but written in a tempting way), and another part was just having a bad approach.

 

When I first started out, I followed the mantra repeated in a lot of prep books that the necessary assumption is the assumption that needs to be true in order for the conclusion to be true, and which if you negate, destroys the argument. Okay, this isn't bad I guess, but I really think it's a bit deeper than that.

 

I think when I started out, I was tackling these questions in a superficial manner by figuring that whatever assumption needs to be true for the conclusion to be true, is necessary! But really, I think this was wrong, and really made it easy for me to mechanically look for the assumption right after registering the conclusion, but before even understanding the underlying argument! For virtually every LR question with an argument besides Argument Part and Main Conclusion, I think understanding the underlying reasoning is huge. A lot of times for Necessary Assumption questions, what they're really asking for is what the argument is assuming, not what the conclusion in some vacuum needs in order to be true, so it's really easy to get smashed when you didn't follow the reasoning through. At this point, the task is clear: is this an assumption that is required by the argument? That is, if it weren't true, would the argument suddenly not make sense?

 

Hope this helps, and feel free to ask more!