1) See whether you can “use” the answer choices
2) Be careful when doing mental math (careless errors)
3) Try to learn concepts (not only formulas)
4) Memorize common formulas/roots/tables
5) Remember there may be a much easier way to solve (it’s called the Quantitative Reasoning section for a reason!)
GMAT Knight - Online GMAT Tutoring
Verbal 99% V48 - Quant Q50 [Section Bests]