I've previously mentioned in a post how to get individual links to open to a new tab but that can be tedious if your doing a lot of posting. This solution is mentioned in a couple of places on the internet if you do some searching but as it's something I've found useful, it's only fair I share it with you my readers.
Go into your Blogger and click on Design then click on Edit HTML at the top just underneath the design tab. Once loaded do a quick search with your browser for <head> and just underneath that enter the following: <base target='_blank' /> so it should look like this:
<base target='_blank' />
Save the template and that's it!