Here are some tips that were a huge help in improving my LR scores. I was about where you were and now my LR is -1 or -2 for both sections.
A big help to me was not to just review the questions I got wrong but to review the entire test.
1.) Do questions 1-15 and then work backwards from 25 (or whatever) to 15. The trickiest questions are in the middle. The end questions are not so hard but are usually time sucks (parallel reasoning and the like).
2.) After I finished with a test I went through each and every question (NOT just the questions i got wrong) and identified the different pieces of the argument. Premise, conclusion, evidence to support conclusion, etc. This was a huge help with method and flaw questions.
3.) I bracket every single conclusion when I'm doing LR. It got so that identifying the conclusion was second nature. Conclusion questions take me the time it takes me to read the stem and see the answer. Probably ten seconds.
4.) After I finished a test I went through all the questions with flawed arguments (which is most of the LR questions) and identified the flaw. Here is a good list of types of logical fallacies.
http://web.cn.edu/kwheeler/fallacies_list.html
5.) I went through all the questions (especially the ones I got wrong) and identified not just why the answer was right but why the other answers were wrong. If you can't figure out why the one answer is right then find out why another answer is wrong.
By reviewing the test as a whole and looking for the concepts that the LSAT is testing I was better able to greatly improve my LR.