How far into the study plan are you after 6 months? I'd say having only taken a single timed section and one full PT, there shouldn't be grounds to make any real judgements about a lack of progress. If your fundamentals are solid and you can do it all in slow motion, you just need to begin to make timed practice of new sections/tests a bigger part of your studying going forward. Personally, I started by doing tests and sections untimed, in their entirety, and transitioning to more and more timed practice of both. Only after doing a few of the timed ones did my score really start to move. What was your diagnostic?

If you're comparing individual sections to sections on full tests, this is bad for three reasons I can think of: first, the concentration necessary to focus for 35 minutes is meaningfully different from what is required to focus for 105 or 140 minutes. Second, individual sections can be lesser in difficulty than combinations of sections from the same test. That is, test makers can make the first LR easier or harder, given that they'll weight the second LR inversely to make the average difficulty somewhere in the middle. Finally, things can get even weirder if test makers decided to make back-to-back easier LR sections, because either the RC section is harder than usual, or the now extinct logic games section was harder than usual. Remember, these test makers are trying to create a certain distribution of scores, not necessarily make each set of LR sections similarly difficult across tests. Sadly, this makes difficulty less predictable. Someone who has access to the stats could probably show how much difficulty varies by section, from test to test.

For these reasons, don't simply practice individual sections or whole tests. Instead, once you're happy with your score in individual sections, begin stacking 2 back-to-back, then 3. Additionally, whole test practice NEVER excludes the experimental section, because that's not actually preparing you to concentrate for 140 minutes.

Now, as to whole test score differences, they can be alarming but remember what you're concerned about are apples-to-apples trend lines, not individual data points. You want to consistently be scoring full PT's within a range comfortably above your goal score. If outlier tests fall below that, no worries because that's expected.

@ktacklesthelsat ok this may sound odd, but there's a sort of intermediate review you can do. Let's say you get it wrong on BR. Don't look at 7sage's explanation immediately. Given that you know the answer you picked is wrong, try to sniff out why that is. Perhaps you overlooked a small word, but more than likely you failed to see the relevance of a phrase or word, you failed to see the implications of the answer, or unpack its logic correctly. If you can come to a conclusion about where you went wrong, then you can reveal 7Sage's explanation. See if your thinking tracked. If it didn't you're probably missing some tools in the tool kit. Just looking at someone else's explanation and things clicking into place isn't the same as actually struggling through the proper analysis. You're creative. Put your thinking hat on and go in odd directions. It's like the difference between being handed the solution book that comes with the Rubik's cube, and solving a Rubik's cube through trial, error, and accumulating strategy.

Are you identifying what's wrong with the answer you picked prior to looking at 7Sage's explanation in the review process?

Conditional logic is also extremely useful when it comes to answer sets that seem identical, but for their designations of sufficiency and necessity. Even if you can keep the flow of the stimulus straight in your head and use that to make an accurate prediction, keeping that prediction concrete while juggling each of the answers can be a herculean effort.

To piggyback on Kevin's advice, I'd say complete as many fresh tests as you can prior to the test with the frequency of test taking increasing as your test date approaches. If you have insufficient untouched materials, then do your best to make them last.

Personally, I did not use a journal, nor do I recommend one with students unless they have specific thoughts on the question or have difficulty recalling their thought process when we review. However, spending the effort to break down every nook and cranny of an answer to understand why it's wrong BEFORE looking at 7Sage's explanation can certainly familiarize you with the intricacies of reasoning, such that the pattern is more likely to embed itself in your long-term memory. So, once you've seen the right answer, hide the explanations. Try to relate it to other similar traps from other questions. There are rare 1-offs, but these are exceedingly uncommon. The more you make the effort to relate a trap or stimulus-reasoning pattern to others, the more likely you are to recall the options the LSAT might explore in the answers.