I think the biggest thing to consider when making a trailer is if you have a place to put it. Because like... Youtube is a completely separate audience than Tapas or any other comic websites, and people don't really go there looking for original comic content? So you're not going to get views on your comic just by uploading your trailer on Youtube.
They're most relevant if you're doing a Kickstarter, Patreon, or private networking, You can also make it a pinned post on social media or pay money to boost the post. Those sites have a better mix of audiences, and especially in Kickstarter and Patreon, people go there specifically to support creative endeavors so you'll get more hits that actually mean something.
A common mistake I see with trailers, too, is that they don't always tell you what the comic is actually about. Pretty imagery doesn't get you very far, you need to be able to convey the themes or the characters or SOME kind of hook in order to get people interested. Why should they care otherwise?
If you don't want to do full blown animation, you can also easily slide around comic panels and other assets to still make it compelling like you see a couple times in this thread! It's what I did too and I think I was pretty successful. This is my Patreon trailer, but it doubles as something I can just send to someone who wants a quick summary of Midwinter:
