Over the past year of tutoring I have come to the conclusion that students need to understand why they are doing things and not just taught how. The benefits of explaining the theory behind an action are that your student will be able to leap ahead because he or she understands at a root level rather than just being able to follow a recipe.
When teaching web design, I have found that it is important to cover the reasons why web standards were developed and what those standards look like in the code. When my students get that "ah ha!" moment of understanding why the tags are used, such as the DOCTYPE tag, they suddenly can comprehend more than just the codes, but the entire history of the Internet. The benefits are that they pick up the tagging and consequent testing much faster. This is important because web design methods are developing and changing at an enormously rapid rate and any budding designer has to understand standards and grow with new techniques or their web sites will not run efficiently, and thus not be visited.
I am also slightly frustrated with the way web design is taught in high schools and colleges because rather than think like a user and visitor, classes are focused on the tools, namely the names of tags and code, their features, and application without much discussion of usability, color theory, communication strategies, design theory, or much at all about content in general. Teaching seems to be stuck in a stone age of HTML tables and tags when developers are moving on to scripting, dynamic websites, tableless CSS, and a heavy reliance on database-based, usability tested sites. Thus, students are being taught to build the HTML framework using older practices, such as embedded tables because they haven't been taught about search engine optimization and separating styles and design elements from content. They are using Photoshop to create the look and feel of the site but having trouble understanding how to move those graphics to make a working site and why maybe Photoshop is not the proper tool to create the pieces of art they want to use. They are also loathe to go back and review the relationships between graphics and code and how a browser works. My goal is always to hand a student the knowledge so that they can pick the proper tool for the task they wish to accomplish.
Students are coming and asking for quick tips and tricks without having an understanding of where the technology is going and what they are actually doing. My most successful students have been the ones who can visualize how a visitor will use their site and then learn to use the proper software and coding tools to achieve their communication goals for their unique purpose.
Bottom line, it is important to take the time and teach the theory of design as well as the history of the web and standards so that your students can grow on their own when your tutoring is done.