Instagram is perhaps the most important platform for photographers and artists alike to share their work, and gain an online presence and get noticed by galleries or potential clients. It is however quite difficult to build your initial following and get your work noticed, which is where the use of hashtags can begin to help.
A good place to start is to think about the content of the work you are posting to try to cater the hashtags you use to attract an audience who is interested in the what you are creating. For example, if you are a photographer working using medium format colour film, a good place to start would be to list the format, film and equipment you are using E.g.
#120 #120film #mediumformat #film #filmphotography #filmphotographer #colourfilm #kodak #portra160 #mamiya
Or if you were instead using 35mm black and white you would then want to cater your hashtags to those specifics instead E.g.
#35mm #35mmfilm #b&w #ilford #hp5 #pentaxk1000 #pentax #filmphotography #grain #film
These are hashtags that people will be likely to look up when specifically searching for work of this type which would get your work promoted to people who ordinarily wouldn't come across it. You can then begin to grow more specific with the hashtags you use, picking out specific elements from within the image you are posting, or conducting research into different community pages who are posting work similar to your own who are open to work submissions.
Another good way to create a collection of hashtags that will boost your work is to take inspiration from the photographers you follow, as they will generally have a strong set of hashtags connected to their posts that are helping them to grow their following, but you always want to make sure that the hashtags you are using are specific to your work so you wouldn't want to entirely copy the hashtags used by another instagram user.
I personally have a few different sets of hashtags that I use for different image types that I post, and where the majority of my posts have a very similar content, I am able to use most of the same hashtags on each post I make.
As I don't want the descriptions of my posts to be too cluttered I tend to post the hashtags in a separate comment below the post. I use a large amount of community page hashtags to increase my chances of being featured on a page, which greatly increases your level of exposure in the relevant communities.