I'd recommend MGMAT SC and Veritas Prep SC. Both reliable, high-quality material, and they'll provide you with different ways of looking at SC.
For strategy, here's the approach I suggest:
Step 1 - Read Choice (A) and Identify One Grammar or Meaning Error
Since we know that a sentence with a grammatical error or an illogical meaning can NEVER be correct on the GMAT, try to identify and name ONE specific error you see. It may seem like there are several things "wrong" with the sentence, so choose the error you feel the most confident about, and write it down on your scratch paper. For example, maybe you think the meaning might be illogical, the sentence overall is awkwardly constructed, and there is an incorrect comparison. You might choose to go with the comparison error first.
What if there is no error in (A)? If (A) seems correct to you, or you cannot spot a grammar or meaning error, feel free to search for a style error. If you feel there is one, such as redundancy or passive voice, make a note of it next to letter "A" on your scratch pad, but DO NOT CROSS IT OFF YET. Remember, a style error doesn't make an option automatically incorrect. It only makes it less likely to be correct. Once you've done this, move on to (B) and look for an identifiable grammar or meaning error. If (A) is correct, then (B) must contain an error.
Step 2 - Scan the Other Choices; Eliminate Error #1
Do any of the other 4 choices contain that same error? If so, quickly cross out
Step 3 - Move to the Next Available Choice; Look for Error #2
If you have more than one choice left, repeat the process. Move to the next choice remaining and look for an identifiable grammar or meaning error. If none exists, feel free to look for a style error and make a note of it next to the letter on your scratch pad. Once you've identified a grammar or meaning error, cross off the letter of that answer choice, and the letters of any other answer choices that contain the same error. Repeat as needed.
Step 4 - Stuck Between Two? Eliminate Based on Style
On a difficult Sentence Correction, you may find yourself narrowed down to two answer choices that both seem grammatically correct and both have logical meanings. Which one does the GMAT prefer? The answer: the clearest, most concise option. If one choice appears to have awkwardness or wordiness or passive voice, select the other option. All grammar being equal, the GMAT rewards clarity.
You can see this modeled here:
https://gmatrockstar.com/tag/gmat-sentence-correction/
