There are plenty of vids and tutorials out there on how to build playlists in DJ software (including Serato). However we always advice to use iTunes for collection management and to make playlists in. They are then easily available in your DJ software.
Adding FX also is something you can learn by viewing many of the video’s on the topic. Be sure to check out the Digital DJ Tips channel on Youtube for example.
Finally, making your own samples is an entirely different subject and highly dependent on the kind of samples you need.