I have to agree with everyone else -- there are no shortcuts on RC, except a solid strategy and an understanding of what to look for as you read. These are my favorite tips to keep in mind:
Always look for at the thesis for the Main Idea. Just like most 5-paragraph essays, the author of a reading passage on the GMAT will typically place his thesis at the bottom of the introductory paragraph. That is where he introduces his main idea and gives his over-arching opinion. If you feel confused about the Main Idea, the thesis is a great place to look!
Take short notes while you read. You can't possible remember every piece of information from the passage, but note-taking as you read will help you recall much more information than memory alone.
Don't skim. If you only read a sentence here and there, you'll never grasp the "big picture" of the passage. It can be tempting to rush through the passage to get to the questions more quickly, but then you'll be going back through the passage inch-by-inch, searching for the answers to those questions! Read at a relatively efficient pace, but read thoroughly the first time around.
Remember that Details support Functions. If a question asks you why the author includes a specific detail from the passage, consider that all the details within a paragraph are generally used to support the function of that paragraph. To answer specific detail questions, sometimes you need to take a step back and ask, what's the function of the paragraph that the detail is found in?
Focus on structure - go back for detail. When you read the first time, think more about HOW the passage is put together, structurally. How does each paragraph fit into the author's main idea? How does the author develop his discussion of the topic? You can always go back for the nitty-gritty details, and if you worry too much about the subject matter it's easy to get overwhelmed, especially if it is especially complex or unfamiliar.
Find the Scope in the first paragraph. The scope of the passage is what ABOUT the topic interests the author. What is his focus? This is usually clear from the first 2 sentences of the passage. If you're having a hard time honing it on it, try to consider where you'd find this passage. Is it a book review? An article from a scientific journal? A newspaper editorial?
Rephrase confusing answer choices. If you're having a hard time making sense of a difficult set of answer options, you can always "dumb them down" by simplifying them in your own words. You have a scratch pad for a reason - use it! It will help you cut through the verbiage and see the choices for what they really imply.
I LOVE RC, and I think you can too with some extra practice
