I was in a similar situation, so I'll offer up my advice.
The biggest difference I made to move from 177 to 180 was how I approached LR problems. I was like you, missing one or two in each section, and there seemed to rhyme or reason to which type I was having trouble with. It was just two hard questions (or sometimes, 1 hard question and 1 easy question that I misread and turned into a hard question.) For these, I would be stuck deciding between two similarly correct answers, and end up guessing.
My turning point was when I realized that I should never, ever guess on an LSAT question. They are designed so that there are 4 wrong answers and 1 right answer - not 1 right answer and 4 almost right answers. If you cannot come up with a reason for every answer choice you cross you, you don't understand the problem. Try going back, looking it over, rethinking it, diagramming it, restating it, whatever will help you (for me, I found rewriting it in simple English helped, removing extraneous words and helping me see the patterns more clearly. I would also spend up to 5 minutes on a single LR question if it took me that long to determine the single correct answer, and not give up when I didn't figure it out immediately. YMMV.)
Anyway switching my attitude was what got me those last 3 points. Promising myself that I wouldn't guess on any more problems, realizing the mistake didn't lie in the test or the questions but with my understanding - it sounds simple and stupid but I saw results immediately. It sounds like this is a problem you're having, so hopefully attacking those LR questions a different way will help you.
Also, just to add my own experience to what other people are saying - I did zero 5 section practice tests before the LSAT, and I also tended to split the sections up and work on them individually. I wasn't strict about timing, for the most part, but I do admit to using the dull pencils trick - it's so much more satisfying to fill in the circle that way!
Good luck
