What size of hashtags should I use?
We recommend to use hashtags that are 10x to 100x bigger than the current number of followers you have. For example, if you have a 1000 followers, you can use hashtags that have from 10.000 to 100.000 posts on them.
Where can I find good hashtags?
You can do that in two ways: by looking at what hashtags your competitors are using (aka influencers in the same niche as you) and by searching for them in the Explore section of Instagram.
A good tip for finding hashtags via the Explore page is to look for suggestions Instagram gives out when you search a certain hashtag. Whenever you search for one, Instagram will pop below recommendations of hashtags you can follow by giving you out similar hashtags based on the relevancy.