Sooner or later you will began to realize that your work is starting to look the same. More so you may get style confused with how the problem should be solved. Because if you look at many of these portfolio sites a good amount of the work would not get accepted by a client and also starts to look the same.
A good way that I learned to sameness is to avoid falling into the same practice of solving design problems. If you just try once a different approach you may end up with a different result. Because you should be listening to yourself. For example if before you start a project you say I would want to have a glass of water and lay down for a few minutes do it. Maybe you want to stare out the window for a few minutes do it.
Since I started listening to myself I began to enjoy designing even more. At times we can get into a routine which ends up in us not enjoying our profession. So therefore stop approaching things the same way and do not be afraid to experiment.
Remember being a lazy artist and falling into the same routine will only produce the same results.