Mobile Optimize WP Blog

I want to make my Wordpress blog more optimized for mobile devices. I'm now using the 2012 theme by wordpress I already did a test if it was mobile optimized and the score was 62/100 as I can remember. I wanted to use the 2014 theme too get it more mobile optimized but when I tried the theme my articles were a little messed up, I guess I could fix it. But I felt like asking first maybe one of you have any tips for a theme or anything else? I did some reading and I understand just changing your theme can make a big difference.

Thanks in advance!

Yes, mobile friendly website is a must these days. Before you choose a theme and activate it, make sure you are going to keep the same theme for a long time as it's the HTML coding Google crawls when on your website. Changing themes again and again can loose the traffic on your site. Choose a theme which can be customized later on. You should stop the crawlers from crawling your site when you do this.

I would like to ask, which tool did you use when you said your score is 62/100. Cheers.