Skysa

Simply set the Twitter account you want users to follow; then, when they click the Twitter Follow button at the bottom of your site, they will start following your account on Twitter. You can optionally set to display your current followers count next to the Twitter follow button and also the language of the Twitter follow button text.
http://www.youtube.com/watch?v=Zj1uGXX2xrk&hd=1 
<a href="https://wordpress.org/extend/plugins/tags/skysa-apps" rel="ugc">More Skysa App plugins</a> -|||- <a href="https://wordpress.org/extend/plugins/skysa-official/" rel="ugc">Skysa App Bar Integration plugin</a>

Skysa Twitter Follow App

Allows your site visitors to follow your twitter account with one click, without leaving your sitet.

Muneeb

Add the Follow Button to your website to increase engagement and create a lasting connection with your audience.
Using as a Widget
When “Twitter Follow Button Shortcode plugin” is activated a widget is also created with title ‘Twitter Follow Button’ you can use that widget to place follow button on blog sidebars.
Shortcode Syntax 
 [followbutton username=’twitter’ count=’true’ lang=’en’ theme=’light’] 
 
 [followbutton username=’yourusername’]
Other Plugins 
* <a href="http://muneeb.me/wordpress-simple-popup-plugin/" rel="nofollow ugc"> 
WordPress Simple Popup 
</a> 
* <a href="http://muneeb.me/wordpress-coming-soon/" rel="nofollow ugc"> 
WordPress Coming Soon Plugin 
</a>

Twitter Follow Button Shortcode and Widget

Create Twitter follow buttons either by using shortcode or use WordPress widgets to place follow button on your blog sidebars.

Skysa Twitter Follow App vs Twitter Follow Button Shortcode and Widget