Why is it important to solve this problem?
1 Deal with CSS files first
The first step is to use a WordPress theme which is efficient and well designed. The CSS files of the theme must be clean and optimized. The CSS files of a blog’s theme is often the main culprit. It is appropriate to purchase and use good premium themes rather than using free themes.
CSS files of plugins also are responsible for this problem. Don’t stuff your blog with widgets. Use only those which are unavoidable and useful (like social sharing plugins). Find out and deactivate useless and slow loading plugins using P3 Plugin Profiler.
2 Use WP Minify
This powerful plugin just needs to be installed and activated. It automatically takes care of the rest of the part. This plugin will surely help speed up your blog.