The way to elicit a specific grammar structure is to model it and then ask a question requiring its use. You could say, for example, "I will meet a pretty girl this weekend. Who will you meet?" gesturing to a girl in the class. If she answers as you wish, good, if not, frown and ask someone else until they get the target language, then smile, and go back to the original girl so she can self-correct. If no one can get the answer, you will have to go back to modelling it, perhaps in more and more explicit ways. There was nothing wrong with writing it on the board.
"Eliciting" has different meanings or applications, depending on what you're going for. One often elicits basic things at the beginning of a class to warm up the students, or to start building the day's context. You could elicit a list of animals from a group of kids by drawing some pictures and asking, "What's this?" After 2-3 animals, scratch your head and pretend you can't think of any more animals. The students will jump in and help. Give them pens and they'll start writing and drawing on the white board themselves--to an external observer, very student-centered.
Eliciting a target grammar structure isn't teaching it, though. If they don't know it, it's impossible to elicit it. We usually call "getting students to say something with new language" production, not eliciting. And the rule for that is "present-practice-produce." What you may have been trying to was get the students to produce "although" and "will" without teaching it first.
Hope some of that's helpful. Good luck with your TEFL course.