GMAT sentence correction

Grammar, most think, is boring
But can anything be boring if it leads to your biggest dream? No, right?  So take a liking for grammar, usage, Standard English, correct English …whatever you call it.
Literate writing is grammatical. To express clearly and effectively- both oral and written- a functional knowledge of the rules and rudiments of English is necessary. You should be able to analyse a sentence, locate errors and modify the sentence. These skills are crucial to language testing in aptitude tests. How and where to use those rules-syntactical and semantic aspects- corresponding to word arrangement and intended meaning respectively-determine your success in grammar based questions.
Grammar-based questions of top exams such as CAT and XAT, present many challenges- long and complex sentences, multiple errors, subtle differences.
Thorough preparation is the key. Thanks to media, we’ve internalized a lot of nonstandard jargon, which we assume are appropriate even in the academic context. Much of those usages are incorrect in a test scenario. Hence you have to both learn and unlearn grammar.
How do you start
If you sit down to learn grammar, there is a mindboggling collection of grammar books on the shelves that examine every nuance from a linguistic point of view. You do not need all these. You just need an aptitude-focused course that exhaustively catalogues and illustrates those usage points that are relevant to graduate level entrance tests.
Stage 1: work with simple exercises in a workbook form covering all parts of speech. This helps to review sentence structures long forgotten.
Study illustrative sentences for those usages- nouns, pronouns, subject, verb, modifiers, conjunctions, prepositions… how they agree with other parts of the sentence.
Stage 2: now you must move on to syntax- various word arrangements in the sentence, the dos and don’ts of sentence construction, sentence variety, effectiveness expressions
Stage 3: work with test related concepts, the format of commonly asked questions, strategies for answering those question types and speed techniques.
Stage 4: Practice with good quality questions, take timed full verbal tests, review areas of weakness.