In this tutorial I'll show you how to set up the opt-in form used in the "Serenity" WordPress theme.
1). To use the opt-in form seen the demo, in your wp-admin go to Plugins > Add New and search for, install, and activate the Optin Forms plugin.
2). Now, in your wp-admin click on the Optin Forms tab.
The image below shows the settings used for the opt-in form for the "Serenity" WordPress Theme. You can of course adjust the settings to your liking.
*For all text, the color code is #3a3a3a. For the button background color, the color code is #bfe0e0. The form background and border color is #eeeeee.
3). To add the form to your blog, copy the shortcode provided towards the bottom of the settings page.
Then, in your wp-admin, go to Appearance > Widgets and add a Text box from your Available Widgets to the Subscription Widget. Finally, paste the shortcode in the Text box, and save your changes.