D&D has so many options that it is very easy to fall into the trap of min/max-ing everything. While some people genuinely enjoy that, I would definitely recommend setting some boundaries for yourself. Design a personality for your character and a few exaggerated quirks which are easy to focus a build around. For example, I had a tiefling mage who was obsessed with fire, to the point of having little concern for, well, friendly fire. The big boomy fire spell wasn't always the best choice for my build, but it matched the personality. It was fun and provided a natural way of restricting the otherwise overwhelming number of gameplay/build options for a new player.