Good design is about simplification. Especially in software design. Focus on doing one thing very well. Know what product you are and which market niche you fill. Don't step outside that niche for that particular product. If a need arises and resources exist to fill a new niche, create a new product for that particular category.
Too much bad software tries to be everything to everyone. Feature creep without a crisp vision of market categories can produce products with tons of features and diffused focus. Ultimately we pay the price in technical debt, huge test matrices and long maintenance release cycles.
This notion of simplicity can be carried into all dimensions. We should stop trying to do so much and only do the things that matter. Easier said than done.
