This will go on for quite a while until you are happy with the result you've achieved. If – after various attempts – you are not going to be happy you will very likely also use some sources of inspiration to develop your idea.
A way which to me is absolutely okay since probably nobody will never be able to reinvent the wheel whatsoever! [Anyway you of course should be very sensitive on this issue – »Yes sir, very certainly, sir! I'll never copy anything, sir!« ;o)]
Well, all the above is part of a process which should be very common to all us designers out there and even though sometimes it's hard to find the right idea it's fun and the only one basis that applies to every kind of creative work we do ...
Now, if you are ever about to create a new logo here's probably one of the best résumés on recent logo-design (short, simple and quite much to the point) you may find on the web just in order to verify sketch.
So cross-check you work and keep on scribbling ;o)