Get a copy of this book:
Nigel Everett "Beyond the PPL" ISBN 1 874783 29 2
its part of the AFE series - covers pretty much everything to get you broadening your horizons in what ever way you fancy and with a strong and appropriate emphasis on how to do so as safely as possible(something that the OP recognises is an aim in itself).
Its important that you do have a plan for what to do next. Huge numbers of post PPL pilots give up fairly soon after qualifying - some, though certainly not all, because they cant see what to do next.
Flying in an environment with others around to offer support and encouragement is important. LAA struts, a club with a good social scene, or joining an aircraft ownership group are all good ways forward whatever the specific flying goals are that you set yourself.
H