What's the purpose of teaching an almost beginner theoretical lines?
Surely a program of mastering fundamentals such as: Opening Principles, mating patterns, basic endgame knowledge, and of course playing a lot, is a tried and proven method of developing very young players, and perhaps not so young players as well.
When the fundamentals become more second nature, one can begin reinforcing them by introducing the player to other tactical elements and motifs, making sure to link them to the Mating patterns and other fundamental knowledge already learned. Pattern recognition is an indispensable skill for a budding chess player, and it needs to be developed early and robustly. Well developed pattern recognition acts like a trigger that often helps you intuitively sense critical moments in a game, which often eases calculation, and heightens your sense of danger. I once knew a talented self taught amateur player, with a gift for tactics, who missed a standard Greek Bishop sacrifice against his castled King simply because it was not part of his basic chess education and consequently never triggered his 'spider' sense.
As the student becomes more proficient with what he's learned so far, its time to acquaint them with the basic elements and features of Pawn Structures, and once again, link it to what already has been taught. Pawn structure is an integral part of Middle and Endgame play so the student needs to have a good working knowledge of what the basic structures are, and how they impact the ensuing play.
Of course I have only scratched the surface of how to go about teaching and developing a young player, but I think I have touched upon most of the important stuff. The main take away to bare in mind, is that teaching opening theory to beginners by rote, before they fully understand and appreciate the principles underlying sound Opening play, can be a very dangerous and counter productive proposition.
Regards,
Toppy