Create a list of commonly confused words, such as "effect" and "affect" and "accept" and "except." Some of these words are found in non-idiomatic expressions, such as "the effects of something," to "effect something into being" or "affect something." Each of these words requires particular phrasings in order to convey an intelligible meaning. Save this list of words to learn for later, when you possess a better grasp of the language.
Replace wordy prepositional expressions with simpler phrases or even single words. ESL learners often mix up common phrases such as "with regard to," writing "with regard of" or "with regard in," which contain incorrect prepositions. Instead of learning these phrases, which are wordy anyway, replace them briefer, preposition-less phrases, such as "regarding."
Recognize old-fashioned, outdated expressions. Nothing is more annoying than spending time learning expressions, only to find that nobody uses them anymore. Learning to correctly construct obsolete words such as "hereafter," "forevermore," "thenceforth," "ere," "afore," "thee" and "thou" into phrases is unnecessary. Spend time learning phrases modern English learners use.