Here’s a context clues worksheet on the verb obtain as a transitive verb; transitively it means “to gain or attain usually by planned action or effort.” Reading these clues, students will probably say this means “to get,” which is of course quite close. I suggest asking them what it takes to get something they want, or variations of that question, and you will eventually induce in them their understanding that to “get” things requires plans and effort.
Incidentally, obtain as an intransitive verb means “to be generally recognized or established: PREVAIL.” It’s seldom used intransitively these days, but a sample sentence (should you decide to develop a context clues worksheet for this usage) would be something like” “In mid-August, hot and humid conditions obtained in New York City.”
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.