A web developer is a programmer who makes websites, and apps for the World Wide Web. A web developer builds a website from the bottom up, developing everything from layout to functions and features on the page.
A good web developer can make almost anything happen on a website, and can build custom code to accommodate the needs of their client. Web developers have an intricate understanding of various programming languages and how they’re used.
A web developer might work at one organization as a permanent full-time employee, or work as an independent consultant. A web developer salary depends on what kind of work you’re involved in, your location, experience and level of seniority.

Not exactly
A web developer is more concerned with functionality and features of a website, and versed in the programming languages required to create them. Web developers will still need to understand the aesthetics and art direction of the site as they implement features.
A web designer will create the logos, graphics, and layout that determine the look and feel of a website. Web designers will use software like Adobe Photoshop and Illustrator to create these materials. A web designer with a knowledge of code can help him/her better communicate with the web developer.

Web development isn’t just building what the user sees. There’s a lot underneath the hood of a modern website, and a good web developer can traverse across the entire terrain.

Constantly keep updated on all the latest web technologies. Languages and frameworks are updating all the time, and so are the latest design trends.
Look at lots of good websites, and figure out how they work. A little inspiration goes a long way. The website awwwards.com showcases the latest in web design on a daily basis.
Learn from those with lots of web dev experience. These more experienced web developers can help you maneuver in the world of web development–not only can they share insights that only those with a lot of experience would know, but they can also give you a better idea of what’s to come.

Personally, I’d say choose a path and stick to it! Learning too many things at once will slow you down. Here are a few ideas of things you can choose to focus on, and a little bit about each one.