GMAT Strategy

courtesy of a student:

Following are the issues I am facing and would like to have advice from you:

1)SC: Poor, somehow not able to apply the rules under time pressure and also getting confused with certain constructions. Also sentences that are completely underlined appear very confusing to me.
2)CR: Have improved in the past 1 week but still sometimes I pick the wrong one out of the two best choices. I am able to eliminate 3 of the answers but getting stuck between the best two. Also getting 1-2 boldface CR every time and though I know the technique to solve it but get baffled by the terminology (‘Generalization', ‘Case at issue') used in the answer choices.
3)RC: Is very inconsistent, as it depends on the passage I get. I do well in science/social science passages but not so well in history passages. Also sometimes I get confused with ‘main purpose' question as I am thinking whether the author is ‘explaining advantages of a theory' or ‘explaining relationship between the new theory and old ones'.
4)DS: In quant I do better but timing/pace is an issue. Most of the DS come after 16-17 questions and that is the time I am trying to makeup time from my previous delay. So get a lot of DS questions wrong from 17-22. Could you please give some of the openers/takeaway for mean, median, range, co-ordinate geometry sort of questions? I have the general takeaways for the above topics but get quite confused with DS questions involving these topics.