How to Create Next & Previous Links On WordPress Posts
There is a function for both the previous link and the next link, both of these functions should be used on a single post within the loop. Both the functions will echo the links out on the screen and will allow you to change the format of the links on the page.
Quick Tip: Next and Previous Posts With Thumbnails
Media rich content is engaging content, right? And giving readers an opportunity to browse through posts linearly is one good way to keep them at your site reading longer, right? So why just give them a title? This quick tip will give you the programming you need to include the post thumbnail and the date of the next and previous posts. Styling is left up to you.