I guess the reason to start an open source project is to scratch your own itch (or because you love doing it). But finding users who will try it or collaborate with you may require some type of marketing? So did you create time to do that or is working on the project reward enough for you?
If you have a popular open source project can you tell me a few things like 1) why did you start it? 2) how did people find it? 3) did you post it somewhere to get traction? 4) do you think it's unfair to just work on something you like but never take the time to get the word out?
The very first thing I did was a presentation of Django at the Chicago Python Users Group. There were enough people in attendance that it led to a few early users. A few of those people blogged about it, and so on.
Django was open-sourced in 2005, and the world was very different back then. No GitHub/Bitbucket and people had very low standards/expectations for the design of an open-source project’s website. The best “marketing” thing we did was to work with our excellent designer (Wilson Miner) on making a beautiful site. Again, I think expectations have shifted here — it’s much more common for OSS projects to have nice-looking sites — but nice design still helps.
That was also before the days of Twitter, and blogging was big. I recall spending tons of time posting comments on blogs. Responding to “reviews” of the framework, answering questions, making it clear that we were listening to the nascent community.
Lastly, there’s lots to be said for great documentation and (sounds silly as I type this) software that actually works / can easily be installed. Again, expectations have shifted since 2005, but you really need to nail this. The best marketing is a great product.