What to Look for in a Good WordPress Theme
WordPress Themes are not made the same. Especially when it comes to looking at free WordPress themes, there are actually a lot out there which are quite bad. To find a good WordPress theme, there are certain things that you need to look for.
Clean with Proper Spacing
You might think that it's an obvious given that improperly spaced or cluttered pages is bad design for a theme but there are a surprising amount of themes, especially free ones, that fail to have a clean theme with proper spacing. This is something that can be easily eyeballed. Look at the theme - How readable is it? Are different elements of the patch distinctive from each other or do they all blur together? In the 21st century, there is no excuse for cluttering a page or theme up with too much stuff.
Colors Under Control
Some themes like to take the typical black / white heavy color schemes and turn them into a rainbow of neon colors. This usually doesn't work nearly as well as you might like. Too many or harsh colors can be painful on the eyes. If you're going to use a theme that emphasizes colors, then make sure it's got a good color scheme that helps the look and not hurts it. If you want to play around with your own custom colors then you can play around on http://paletton.com/ to help get you something that works.
Designed for Your Purposes
Different themes specialize in different kinds of sites. While there are themes with sub layouts and multiple designs to support as many site types as possible, you still need to find out what actually works for you. Are you making a business site that needs a front page that converts traffic into customers or just a personal blog. When it comes to artistic or photography sites, there are many more unique ideas that seem to go over well. Find out what aspects of your site you need to emphasize - content, media, or whatever - and find a good WordPress theme that meets those goals. Some of the better themes may be a bit more customizable so you can get your site closer to the image you have in mind.
These days, it's almost always a bad idea to not make an effort to have your site support mobile devices. Good WordPress themes are usually responsive themes that reshape their layout as the browser width shrinks. This means that when you scale screen sizes down to a tablet or mobile phone that the site will display in such a way where users can still browse from top to bottom ideally with no left and right scrolling. Pleasing your site's mobile traffic audience can only do good things for you so find a theme that looks good on both desktops and mobile.