I thought I recall reading a great "how to ask for help" post in one of your other forums, but I don't think it's on here.
I think it would be worth adding to the Get Help forum and making it a sticky, so it stays on top of the list. It might help head of some of the uninformative posts like "______ doesn't work. Help!"
Sorry - I see you already have something like this in the About the Get Help category topic. For whatever reason, it's not staying pinned to the top of the list in that category for me. (also, when I click on that category in the Get Help listing, it takes people to the bottom of the thread, so they may miss the descriptive text above.)
This not staying pinned thing is another of Discourse's peculiarities. Users can unpin a pinned topic they've already seen for themselves, and the stock config also had this happen by default once you've read a pinned topic to the end. I've since disabled this setting but you probably read the topic before I did.
I'm also looking into writing a little theme component that will inject a link to that topic plus a "please provide logs!" on top of the posting form. First experiments on Friday looked promising, I just have to figure out some stuff about the Discourse JS API and then that should be a go.
You probably already thought of this, but... if you are including "please provide logs", please also include a link to something explaining how to get to the logs. I'm constantly forgetting, so often omit the "include logs" request in my attempts to help.
That was the plan 
This is now live. Took me a bit of head scratching (I never did anything with Discourse nor Handlebars so far) but I have now won:
This will only show up if one is about to create a new topic (so not when replying to an existing one), and only when no category or the "Get Help" category is selected.
edit new screenshot, changed the wording a bit
You may want to add an explanation there about how the "mark as solved" feature works. i.e. the little check box.
@Tone it is explained in the "About the Get Help category" post (incl. screenshots), and the space in the edit dialog is extremely limited, way too limited to repeat that there yet again.
I noticed. But not everyone reads the instructions!! How about this: appended to the "Additional information..." section. "Check the box for the solution when found."
I've seen you post that reminder a few times. 
How about this?
But not everyone reads the instructions!
To be quite frank, after over five years of maintaining this project, it feels more often like "nobody reads the instructions" but if people want help maybe they should start doing that 
That's better.
Too True! I think smart people think they can figure out most things and they skip the instructions. Sometimes the instructions just have to bump them in the head as they go along. 
