Marketing is becoming ever more important these days. Not just for people trying to sell things (like me) but even for artists trying to get their name out there. The word "marketing" has some negative connotations for most people but if done right it can be beneficial to both parties.
There's a difference between marketing and advertising. Every artist should market themselves on social media. If you provide a service or product -i.e. Gumroad- it's worth looking into advertising.
In an ideal world, you would just focus on making good content and people would find it, but there's so much noise these days that it's an unlikely scenario.
If you're selling a product or service, Adwords is a great way to boost views. The best tip I can give you is to limit your amount of keywords. I get 80% of my clicks from 2 keywords. Try to achieve a good Click-Through Rate. A high CTR means people are more interested in your ad, so they'll be more likely to convert. Depending on what you're offering a good CTR would be 5%+. I average 20% on 1 keyword. Also, it's best to switch to manual bidding, in my opinion, since I don't trust Google's automatic bidding. If you're a freelancer you could put out an ad for when people search "freelance 3d artist" or similar keywords.
If used properly GA can be a great asset. For example, you can link it up to Google Adwords so you can see the exact ROI of your ads.
I've dabbled in both but I think you still get the most bang for your buck with Google Ads.
I use Buffer to plan posts for Twitter and Facebook simultaneously. As well as providing a nice dashboard for your social media accounts. https://buffer.com/
An interesting tool that generates a "heat map" for your website. It's free for a single page. https://www.hotjar.com/
Has interesting stats on different Twitter hashtags. https://ritetag.com
There's a nice list of tools here https://social-media-tools.zeef.com/constantin.colac
Contagious: Why Things Catch On https://www.goodreads.com/book/show/15801967-contagious
Likeable Social Media https://www.goodreads.com/book/show/10220557-likeable-social-media
Twitter is not your blog. Sorry, but I don't care what you're having for breakfast.
Don't use Twitter or FB just to market your products at people. Try to engage with your audience and share interesting things. I've definitely been guilty of this before.
Try to respond to every. single. person.
Email marketing is still one of the best ways to engage with your audience. Releasing free products or tutorials is a great way to build an email database to send newsletters.
Timing is incredibly important! Don't post important things at 3 am on a Sunday. The sweet spot for me is 1-3pm Tuesday-Thursday. Buffer has a tool that can find the optimal times to post.
Examples of good marketing
Marmoset features a ton of artwork. This is mutually beneficial as both parties get exposure. https://twitter.com/marmosetco
GameTextures shares a lot of interesting content, as well as creating tutorials and articles. Instead of exclusively marketing their own content at people https://twitter.com/GameTxtures