1 - Make sure your blog has a search box
Nothing is more frustrating when I remember a past post from a blog that I want to re-visit. Only to find the blog doesn't have a search facility! Very frustrating having to trawl through the whole blog to find that one post and it usually ends in me giving up.
2 - Create a contact page with a visible, clickable email address
Contrary to popular belief this does not result in a lot of spam email (although do expect a little). It does however make a difference to the opportunities you will be offered. PR's can add your email address to their contacts list - they can't do this with a contact form and will simply move onto the next blog.
3 - Bloglovin
Most of us read blogs via bloglovin. It is frustrating when you stumble upon a lovely blog that you can't follow on bloglovin! It takes two minutes to sign up and add a badge to your blog. Bloglovin provides you with loyal, regular readers and to me it's a no-brainer!