Tips and Advice required for backpacking in Europe?

I am about to start planning my first backpacking journey from the UK which will last for around 6 weeks. My plan is to start in September and return by mid October. My travel is mainly for adventure, photography (landscape, architecture), history, learning, meeting people. I appreciate any advice, tips on the following:-
a)Budget
b)Suggestion of any destination in Europe and period of travel
c)Method of traveling
d)Safety
e)Essential items in my bag
f)Dos and Don’ts
g)Worth while joinning backpacking tour instead of solo-ing? Suggestion?

Thank you in advance !! =)