Graphic Design for developer [duplicate]

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• Developer to Designer path: How To 5 answers

I'm a experienced developer on C++, Java. Currently I'm developing my site to show my apps and my work. I've seen many beautiful sites of front-end developers, agencies and companies. For example: - http://ift.tt/JIJeu7 - Portfolio in awwwards: http://ift.tt/1AddOdv - And others.

What is intriguing me is how the can combine fonts, colors, shapes graciously. Some android apps have beatiful icons and interfaces.

I would like to know resources to learn some techniques applied on design to make my work better and improve my site layout. Can you point out what do I need to learn?

Please remember, I'm a software developer