Hey Dan,
There is no “how-to” category per se, I would just put the “how-to” language in the title of the post under the tutorials category if you decide to post a how-to.
Instead of “requesting” tutorials, rather I would encourage people to just post a question in the appropriate category and our forum community will respond (perhaps with a tutorial).
If you think the SketchUp team should do a tutorial or skill builder on a particular topic, please check out the Skill Builder thread and fill out the feedback form linked there or comment on that thread. Click here for a direct link to the feedback form to submit your idea.
Thanks,
AlexB