Ya many downloads come from word-of-mouth recommendation.
Also if you often update your addon (if needed) it gets more downloads.
You are right by linking to your other addons on the bottom of every addon page = if you like this addon you like this addon to maybe.
When I look at your addon page a problem is mabye the names of your addons.
Try to avoide words that stick together and discribe as much of the the addon as possible in the addon titel (thats not looking super cool but it will help ppl find your addons on wow UI and other sides the titel of the addon is
SanityCheck
=> Rename to:
Sanity Check (wrong gear & missing buff checker)
=> just an idea
Now if someone searches in search addons for wrong buff check your addon will popup
Currently there is no way to finde your addon noone woud search for SanityCheck (though its a cool name). Test this by yourself if you can find your addons on wow UI by the things they do and if not rename them.
"Intoxicated" is also one of the names I woud discribe more - as a german I had to google this word
You coud search in the forums for ppl who have problems that you solve with your addons and give them the link to your addons
Also a very effective but reluctantly used methode is to name your addon similar to other well known addons that do similar things as your addon
