Camera help for a numpty

[RosscoPCole]

Currently I have an Olympus Pen epm1. I love the size, but am finding that the quality of the photos has dropped and they appear very subdued and lacking in vibrancy. I do not want to use Photoshop to alter all my pictures.

This could be that the sensor needs cleaned. I've never done this before, how do I go about it?

What kit do I need to do this and clean the lenses? Would this make a big difference? How do you store your lenses I don't want a special camera bag. Would lens cases make a difference?

Help!