Hooking up with another PPL is excellent advice. My only comment would be to make sure you don't do that
every flight, or you'll risk loosing the confidence in your ability to fly without another pilot sat next to you. But having someone take half the workload off of you makes flying even more pleasant than it usually is - not to mention that you'll have someone to talk to!
Apart from that, try to go further afield by yourself. A landaway at an airfield you already know from your PPL training would be a good start. Once you've done that, a landaway at an airport that you don't know. No need to go too far - just pick somewhere you've flown past a few times but never actually landed. You could also find some interesting landmarks to fly over, without actually needing to land. And start taking non-flying passengers as soon as you feel confident enough to be able to do so - they'll no doubt have ideas of where they'd like to go, and the additional challenge of having to answer their questions will make things more interesting.
Also, practice all the things you did for your PPL from time to time - PFLs, stalls, steep turns and so on. It's fun, and it's also vital to keep current at those skills. Probably best not to do this with a first-time passenger, though.
I wouldn't recommend doing more training immediately - the most important thing now is to gain the confidence in yourself to be able to go flying without it being a major ordeal. But once you've done a few flights with passengers, to new places, and so on, there's a whole load of new things to learn. You could do an IMC course, a night course (probably easier in winter when nights are longer), a tail-dragger conversion (this would be my personal recommendation - it'll improve your flying, it's great fun, and it opens up a whole new world of interesting aircraft!), aerobatics, get an instructor to check you out on cross-channel operations - the list is endless.
Well done on your PPL, now go and have some fun!
FFF
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