Design is a fluid process, something that will change with each project, each challenge. Intuition is often a good starting point. Following the well-trodden paths which are influenced by long standing principles is another.
Design is not something you ever stop learning. Whatever your background or experience, there's always more to learn. Consider this a journey which will allow you to keep growing your skills :)
Let’s take a look at some established as well as popular graphic design principles and their possible inspiration for design for the web. While working on your first mini project, start your initial design process by considering how some of these established concepts might contribute to your design.
There's a possibly fitting course on pluralsight I thought I should mention. I've not had time to check out all the offerings in our new access to pluralsight - but I had a quick look to see if anything would fit our topic - and there's one you might want to have a look at: The Fundamental Gestalt Principles - Understanding Perception, part of An Introduction to Design By Jason Roberts. If you do have a look, let me know what you think :)
The publication ‘Dear Design Student’ is an excellent collection of various articles by industry professionals, written for design students in answer to their questions. I’d highly recommend that you check out these articles. Excellent reading and plenty of food for thought.