It's very difficult to give a blanket "best method" for converting hand drawn images into vector art. As I'm sure you understand, each image may require a different technique and different tools.
Adobe Illustrator's Image Trace feature is very handy at converting inked or solid drawing scans into vector art. Adobe has several Image Trace tutorials you could experiment with to determine if this method is fruitful for you.
Beyond that it's really a matter of understanding Illustrator and the tools available. There is no simple quick method other than Image Trace. You merely need to understand how the Pen Tool works, and the tutorial you already linked to is just as good as any other. There's just a lot of practice to get proficient. Sketchpad.net has some good basic operations tutorials about how the tools function, focusing more on use than on creating the latest "trendy" image or doodad.
Illustrator's Width Tool can also be a very helpful feature for drawing content other than geometrical shapes.
There are other third party tools which can assist (after you understand the Pen Tool), such as plug ins from astutegraphic.com like VectroScribe (if the image are more geometrical in nature) or DynamicSketch to assist with creating more nature feeling vector content. There's also XtremePath from cvalley.com which can help with some path operations. These are all additional costs and only you can determine if they are worth your dollar. For my money the Astute plug ins are well worth the price.
As for the Wacom tablet, it can be helpful, but really only if you are sketching directly within Illustrator (DynamicSKetch with a tablet is fantastic). The tablet won't be much help trying to clean up scanned drawings. That being posted, I do use my tablet 100% of the time in all applications. But the nature of Illustrator is simply click, click, click-drag, click. A tablet doesn't really change that work pattern.