IT'S SUBJECTIVE.
If you haven't noticed by now design is a subjective trade. Similar to our taste in music. You and I are unique because we're individually influenced, and we classify good design differently. So how can we identify if our design is good? Cause what's good to you, may not be as seductive to me. Kanye West said a line that resonates here. "For me, first of all, dopeness is what I like the most." Kanye's dopeness is loaded with personal introspection. Again, it's subjective. If I may dissect, he's tying all of his personal experiences, idea of taste, visual appeal and constructive criticism to articulate something intuitively dope to him. Keyword, himself. Simply saying dope may be misleading to the untrained eye. Because what's dope to him, may not be dope to you. If we formulate dopeness, it means 3 things: aesthetics, crafted intention, and unwavering confidence. Good design is the sum of all three.
AESTHETIC
Own a look like Picasso owns Cubism and stick to it. Be consistent in applying the look. If you're working with a family of things, define a common style to tie them all together. It's best practice to choose a look that fits your project, and retain it all the way through. I'm not asking you to stick to one style for the rest of your career. Just stick to one style for the rest of your project. Visually it'll be perceived as aesthetic confidence. You'll thank me later. In the industry we call this Design Language. In the long term try other design languages. The best designers adapt different styles over time.
CRAFTED INTENTION
Good design is not just good looking objects. Having a beautiful object but a weak idea, is like building a skyline with shit foundation. It's a tall tale with a weak plot. Eventually it folds into itself. You'll be surprise how far a strong and deliberate idea goes. Seth Godin said it best "No one is asking you to be that person who invent something that never exist before." I believe the best designers identify a problem space, finds the solutions that already exist, and bring them together. For example camera phones. At some point in history it became cumbersome to lug around a film camera, and rolls, and rolls of film. At a one-point someone saw the opportunity to combine the camera with a memory card, and inspired a shift in camera technology. Cameras became smaller, thinner, and lighter. Small enough that at another point it became cumbersome to lug around a digital camera and a cell phone. Someone saw the opportunity to combine the digital camera and cellphone, and inspired a shift in smartphone technology. We're not asking you to design something that never exist before. Truthfully we are curators of the present, we identify the problems we live with today, we orchestrate and combine solutions that already exist, therefore we design for the future. This is how you build strong ideas. Qualify it with real world science, the more realistic the science the stronger the idea.
UNWAVERING CONFIDENCE
Lastly be your number one fan. Like Kanye, loves Kanye. Be proud of what you produce, and don't produce anything you're not proud of. Unfortunately there is lots of vanity in being a designer. Yes, be humble but also be bad-ass. You have a to command a level of respect for your designs. Companies hire you for your subjective opinions. Have confident in your work, because If you're unsure so will your cleint and audience.