Design is about leaving a lasting impression within the boundaries of your industry. The first step is starting with researching the industry and competition. Creating a list of the features and functionality that are useful.
Next up, I experiment with different layouts using Bootstrap 12 column grid. Lately Bootstrap has been my go to responsive framework, they have great browser support for Android, iOS, Mac OS X and Windows.
The use of color really depends on the current logo. I found this great resource online lavishbootstrap. This sites lets you generate your own color scheme from one of your favorite images that you can upload right there on there site.
Good fonts and professional images are like candies for your eyes and they help the viewer connect with the written content on the web pages. Also using hierarchy while placing elements within the grid of the layout, helps to distinguish important content and brings balance to the pages.