Many ESL grammar instructors understand that grammar rules are abstract concepts which in and of themselves hold little meaningful value for adult ESL students, learners who are less interested in "memorizing" bits and pieces of the English language and more focused on using it as a means of communication in order to access educational and professional opportunities.
One method for engaging adult ESL students (especially those with strong educational backgrounds) in the study of rudimentary grammatical forms is to have them connect the English language to their own lives.
The term philosophy has various meanings, but for practical purposes we may choose to define it as an analysis of basic beliefs that form an individual's view of the world and their intended interaction within it.
In other words, the choices we make and the actions we take based upon what we believe to be true forms the basis of a philosophy.
Adult ESL students have a wealth of experience and prior learning to draw upon as they engage in the process of studying English, and the choices they have made form the essential qualities of their character.
Explicitly establishing that the way we personally engage in life is similar to the process of how we communicate our ideas: We make choices.
Having determined that the study of grammar should be viewed as a continual series of choices from which thoughtful decisions must be made, adult ESL learners will have a better sense of their empowered role in their own learning, a role singularly similar to their own lives in which important decisions must be made all the time.
Assign the class a short writing assignment in which they write about a time when they gave advice to someone without thinking carefully about the advice they gave, or when they had received advice that they felt was not fully thought through, and have the class include a "what happened" explanation.
Then, introduce (or reintroduce) two grammatical forms and ask your adult ESL stdents to revise their writing to fit one of them. Two examples might include compound/complex sentence structures (with but, however, even though, etc. connectors) and writing in a series (e.g. first, second, after that, then, etc).
Now your students will need to make a choice about which grammatical form is most suitable to what they had written about their advice-giving (or receiving) experience. They may choose to write in both forms and then chosse the one that makes the best sense or has the better style. Some may prefer their original writing, but they should be encouraged to explore the alternative methods prior to making a final decision.
I encourage you to read an excellent article by Suite101 writer Dorit Sasson which provides a clear explanation of the need for change in 21st century ESL grammar instruction, an aim to which the concept above aspires.