It doesnt make a lot of sense but theres a few things to do that will help a bit, then after that it just seems random whether people see it at the right time or not.
This post i would tag as: art colorchallenge blue whalepower minnowsupport
Use these tags on all posts: whalepower minnowsupport
It will help you get some attention from someone that could boost your reputation with a good vote which will help. @minnowsupport
If you can add any info about how you painted it, what paper, paints etc - it will help show your knowledge, that its your work and your a good artist to follow. Theres a lot of people faking it and they always leave out details on the artwork process, materials.
Try and make some step by step / progress posts with a bunch of photos showing the work being made so people can see your work is real, it would be great to see the process! That will remind people your work isnt just old stuff but your still producing new art to look forward to.
The fine arts seem to be harder to get attention on steemit compared to cartoons and sketches but theres groups forming out there like @aksinya and steemmarket
https://steemit.com/steemit/@paolobeneforti/steemarket-is-online-buy-sell-your-artwork-for-steem
Follow and let them know your an artist to be added to their list.
Give upvote projects a miss. These are diminishing returns, with the guys behind them cashing out very nicely. Just put the effort into building relationships. There is no jumping to the front of the queue.