Learn a technique and play with it for awhile. Learn a second technique and play with that. Put them together and play with the combination... when all of these techniques assemble into a system it turns out to be a tinker-toy construction incapable of doing a job or supporting weight. In the martial arts, this is where the instructor steps in to explain the 'advanced aspects'.
That is so, so wrong. The advanced aspects, too often, are principles and strategy. These are the true basics.
Every real system has some things in common: they evolved in a specific environment; they addressed a particular type of threat; and they revolved around a strategy that respected those two facts.
Given that these are the central essences of a system of self-defense or combat, why are they considered advanced? These are the basics of the basics. the things that make everything else make sense and, possibly more importantly, if something doesn't mesh with these core values it doesn't belong. Splitting your strategy weakens everything. (Theoretical example- if the core strategy of your system is to pull someone close and strangle, where does pushing away fit?)
No matter what you incorporate as physical basics- footwork, power generation- make sure your students understand two things from day one:
1) The problem the system was designed to deal with. One of the most popular systems around was designed for the sole purpose of beating Japanese karate in karate tournaments of the 1950s. It is masterful at that. My system was designed for medieval emergencies. It wouldn't work well in a 1953 karate tournament. If the focus is on self-defense some time has to be spent on how criminals think and act and how assaults happen. You must learn diagnostics before you can apply the cure.
2) The strategy chosen to deal with the problem. Different strategies can deal with the same problem, that's fine. Mixing strategies or adding techniques to a system that are incompatible with the strategy just create confusion. Trapping is an aspect of controlling the movement of the threat. It is feasible, maybe critical, for a strategy of "Control the arms to create an opening". It isn't compatible with a more brutal "Close and do damage" strategy. Techniques or types of techniques should only be added to systems if they serve the strategy.
This doesn't mean "don't go out and try new stuff." One of the things you need to prevail is something that I can only call 'clean'. Just as mind, body and spirit have to be in accord, strategy, tactics and techniques have to work together. If they are at cross purposes, the entire structure is weakened.
Strategy and threat assessment are basics.