Well the answer depends upon your site.
Let's understand bounce rate first. If someone clicks into your main webpage and then leaves it without any interaction, then that is considered a bounce. The bounce rate is the percentage of clicks that bounced over the total number of clicks into your page.
If you only have a straight one page webpage, with no calls to action (e.g. product pages, or contact forms, or other pages, or blogs, etc) then you will probably have a high bounce rate. And it is not really a trackable metric that you would be interested in.
But it is a factor if you have interaction points on your page, for example if you have an ecommerce online store, or you are trying to encourage signups. If there is a high bounce rate you need to determine what is causing the bounce, which will be a process of elimination.
First you need to check if people that are finding your page are not actually finding the answer to their query. This is all about keywords. Sometimes you might be rating high in a keyword phrase on the search engines that have nothing to do with your actual business. That might be great statistics for your business on impressions, but the whole point of your website is to attract your target audience. If there is a keyword that you are rating for, that is not relevant for your business, try to work out what on your page is attracting that keyword - is it a certain phrase, a blog article, file or product description. Adjust the wording in the culprit, or consider setting your robot.txt so that search engines don't crawl that item.
Drill into if it is a specific channel source that is experiencing the high bounce rate. For example, if you are utilising advertising, check that your advertising is relevant to your business and is not click-bait orientated.
If all your keywords are relevant, then look at the landing page for the actions that you are trying to encourage.
Don't forget that there are a number of areas that you can check bounce rate in Google Analytics - the audience overview, the channels report, the All Traffic report (for sources), and the All Pages report for the individual pages.
Well every site will be different so you should be comparing to your history. But some indications of website type bounce rates (from Customedialabs) are:
There is variance across industries as well as you can see from these average bounce rate benchmarks:
This should give you a starting point to looking at your bounce rates and to start working on improving them.