I've only recently started blogging 2 months ago, but I've noticed that my social presence has increased a bunch since I have something to share other than listings. I've also been able to network with a few people because of my blog. I can see how it's a good investment, but it's a SLOW burn. Of my few sales, half are from my blog exposure.
I would suggest blogging about something you love doing and don't mind writing about consistently. I blog about art tutorials, art books, and cool artists I find.
You can start off for free at tumblr, wordpress, or blogger.
HTH,
Roux