You've probably heard of Grammarly. A two-minute silence for those who haven't... Grammarly is your trusted content enhancer and proofreader. It has a free version; which takes care of significant errors that are recognizable to the average reader, and a premium version; which spots any advanced errors your content might have. You can go premium by paying up.

Grammarly has a Chrome extension as well. No Android or iPhone app, unfortunately. 

TitleCapitalization is your absolute need. If you have trouble adding upper cases to your headings or your titles, use TitleCapitalization. I use the third option they have—this is the only one that sounds legit. You can copy/paste your faulty headings and titles and then do the same and place them wherever you need to. 

It would reflect positively on your writing if your titles and headings are properly capitalized.

This tool has no app.

Not exactly a tool, Webster. This dictionary is one of the most-used dictionaries out there. And one of the most-preferred, too. Webster has a word-of-the-day option which every budding writer needs to dedicate their time to. Combined with the thesaurus and the interesting blog-like posts, Webster makes for a perfect dictionary that not only deepens your vocabulary but also adds to your knowledge.

Merriam-Webster has an Android app.

Medium is what every opinionist out there should write on. It's a blogging platform where writers from all around the world publish their pieces. It has some convenient writing features and a gorgeous user interface. You can also read posts that you like and leave your reviews. 

This blog post will get you started. 

Medium also has an Android app. 

Evernote is a note-taking utility with more features than you could ask. It is best suited to planning your writing, giving it structure, and having everything organized. It can be used as your daily note app as well. If you have a messy workspace when it comes to your articles and their deadlines, Evernote is your tool. 

There's an app that will come in handy. 

Revolutionize your writing journey with these tools and even more that are out there, and stand out from the crowd—in a good way.