It may be useful to think of it this way. System development is a very private and solo occupation. You work alone a lot. The test for whether or not your system works tends to be objective, technical and quantitative, and does not involve a lot of people directly (unless you screw up the schedule).
On the other hand, visual design (apart from the actual code writing) is a very public occupation. Unless you don’t care about a viewer, the test for whether the project succeeds is qualitative and subjective and, apart from actual functionality, not technical. This is just the opposite of what you’re used to. There is simply no right answer. (BTW, this can be maddening, especially with a domineering boss.)
Therefore, if some acquaintance with visual design is a priority, probably it is important not to work solo but to get your designs in front of people - especially people with some artistic inclinations - as often as possible. This will allow you to get used to the idea that your projects will be scrutinized by lots of people with perhaps very little technical skill. (This could be initially like a soak in ice water.) If at some point you DO NOT get excited about showing your work to others, and about their reactions, then perhaps web design is not the right occupation for you.
I really have no proven advice. Maybe this will work. Take a beginners class in graphic design (not drawing or painting but hard-core graphic design - and not a course for web developers but one for designers.) In the course you will do small projects which will be examined and commented on by the entire group. Besides learning about design, this may get you more enthusiastic about the group aspects of web design. In addition, interacting with a group this way may get you more excited about the public aspects of web design.
Also, look at designs in magazines and catalogs, and try to discuss what you see with others as often as possible. Go up to strangers in coffee shops and ask what they think. Why not? This might charge some batteries.
The previous commenter has a method that works for him. However, I would not recommend this in general. If you have no experience with design, you should look a lot at designs, interact with designers (in a course, for example) and get other people’s reaction. Eventually you may (or may not) develop a style, but don’t force it. Keep it loose and open. At this point you probably have little to offer, so don’t insist on your initial ideas.