Validate your site's #HTML with this great tool by #W3C. Certainly pointed out a few things to me that I might have missed if I hadn't checked my own site. https://validator.w3.org #webdev #design #webdevelopment
@FreePietje Yes, I found the CSS a little later. Will definitely be using them both!
@syntax I learned a great deal from using that tool :)
Also, don't forget to validate your #CSS as well: http://jigsaw.w3.org/css-validator/