Well...
Teaching in Düsseldorf I asked my students about the most obvious difference between design and art. Great disscussion, people being ready to kill!
A designer has always to solve a problem and his most important task: find out what it actually is! An artist does not have this pressure.
Concept
Empathise — allows setting aside own assumptions about the world in order to gain insight into users and their needs.
Define — establish features, functions to solve the problems.
Ideate — generating ideas, brainstorm and brainwrite.
Prototyping
From the very beginning of a project it is important to test each element and to ensure that it all works as intended. Navigating around a working prototype and trying out different actions allows you to experience what it would be like to use the interface.
Favourite tools: Principle and Framer
Creation
Find out the minimal esthetic language to achieve the necessary result... and there is no such thing as "unused space" or "strange color". Right now most of my work is using Sketch, InDesign and Illustrator. Hope that very promising tools like InVision are grown up soon.
Coworking
Agile in all things... Every design has to be conform with the platform it is made for. Whether a mobile device or a desktop application, there is a lot of communication with experts who actually develop and code. As for tools so in my experience most teams use YouTrack or Jira.
and outside of everything else - entrepreneurship, art, photography, filmmmaking, writing, traveling,
running, climbing, snowboarding, caffeinating, reading a lot of sci-fi, talk to crazy start-up guys, learn japanese,
look up to people like andy goldsworthy and enki bilal