The main reason you are not getting subscribers in your website, you don't have High Converting Content. and Strong Call to action. and also a Lead magnet that has Massive Value. I would Create a Good Incentive that Most visitors want to subscribe and Run a Call to action that grabs Their attention.
This article is very helpful. Get Your first 1000 blog subscribers
These are Simple and effetive Things You Need to Implement In Your Blog. Getting Organic Traffic to Your Blog and Getting No leads, its because you Don't Provide a free Offer That is relevant to the same article. Which called "Content Upgrade" many successful bloggers had great success with free packaged informations and Gained thousands of loyal subscribers. If you Could Spend Some Time Researching For The Best Info and Offer It as a Free Bonus Then You Will have Many leads Coming To Your Blog every day.
Using Your landing Page is Not Enough. You have to Study as many landing pages as possible to know which one Converts Better. Testing is a Great Way to Know The best Ones.
What to offer to your subscriber :
Some People don't know what type of Offer they package for their readers. I think Something New and Unique is a Powerful Strategy. Find Something Readers want but can't find somewhere else.
To get enough subscribers, you have to make sure You have a pop up box in your blog. i know its annoying but it works awesome. Especially when you have an amazing offer that most visitors need.
I would Create a Free incentive about " how to create viral posts " instead of how to get Create Visual images " the first one converts better because everyone wants to know how to write viral Blog posts.
if you have a tight budget and using wordpress platform in your site, i suggest popupally free plugin, easily edit in a minute, you can use it with mailchimp, aweber and other autoresponders.