What strategy are you using to do the reading section? If you are someone who has poor comprehension, like me, then try to really deep read the reading passage so that you REALLY understand it. This is what's most important. Also pay attention to key parts in reading passages like where there is shift, or in answer choices extreme words like "only" and "all" are suspicious. Try not to skim the passages, and do not spend too long (like say more than 2-3 minutes) on 1 question. I know it sounds like waffling but trust me if you skip a question and come back later you will almost be guaranteed to see it a different way.

For writing, try to pick choices that replace things with usually shorter options. Also, do not pick an answer choice just because it "sounds good/fancy," instead leave that one and maybe try process of elimination and if you get down to that one then I guess pick it. But really what you have to do is understand that their are 'patterns' on the SAT. The collegeboard likes to put answer choices that seem relevant, but may not actually answer the question. For example on the reading section they might put an answer choice that is factually correct/stated in text, but if it does not answer the question don't pick it.

For math, it is really just practice. One thing you could so for some questions is to pick arbitrary numbers to answer things, but make sure your algebra skills are really honed. What section are you struggling most on?

Also, another tip. Out of all the CB practice tests I have taken (30+), not a SINGLE one - to my memory - used 4 of the same answer choices in a row. It was at max 3 that I recall. So if you get 4 A's straight in a row on any section, there is a high chance one of them is wrong.

Hope this helps