When it comes to UI be it for a web application or mobile, there are innumerable ways to make the visuals. The design should not be exactly similar to the wire frame; the wireframe merely acts as a guide on how you can go about the design. The UI stage of any project is one of the most iterative stages in the design process. You may design in one way, someone else might do it another way and the clients may want/expect something else. Making your design similar to the wireframe is not going to help you become a better designer. Keep the wireframe as a reference for positioning of any elements if necessary, but the rest is up to you. Come up with something totally different, try different layouts, fonts and colours, and just play with the UI as much possible till you reach the stage where you feel it looks right.
Clients appreciate if you can come up with various options in visuals. They may have already checked out your wireframe in the previous stage, and giving them something similar to that is not going to win you any praises. Experiment with styles and approaches, and for all you know, clients may love your experiments and give you valuable suggestions and feedback.
