OK, simply put, I don´t think there is much to say about copy in terms of artistic expression, copy means copy, copying something existing either for the purpose of learning or stealing for whatever else reason but the result will never be something original.
The difference between inspiration and influence is far more difficult;
I will not cite Wikipedia here, I´d rather share my own view about that matter and invite you to discuss in the comment section.
I see inspiration as something that can´t be grabbed, a holy grail if you´ll call it so, the untouchable artistic spirit also referred to as muse, if you watch the video tutorial on dtuts.com or the image to the above - one can see some inspirations from Clive Barker, the band Tool, The movie Pan´s Labyrinth and Brom.
These are indeed inspirations, but not necessarily influences, they have rather fleetingly had a remark on the development and the desired outcome.
For those of you interested in the process of the image, the video below is a teaser cut to roughly 5 minutes that you could spend while reading the rest. I´d appreciate if you will head towards the full length and of course free video tutorial here
I think there is nothing wrong with "being inspired" or "being influenced", in fact the opposite is true. Sometimes it makes it easier for art-buyer, other artists or just interested parties, friends or co-workers where you as an artist come from.
But I´d like to differentiate between these two terms very strong, because influence can be a bitch if you´re as artist too much in love with another artists work, yes even the reason that you started to paint like a maniac, the result is a one sided and very easy to recognize style, that will put you in a drawer sooner or later. I was in that trap in very early years and it took a long time until I found out how to fix that: with inspiration.
"If it were about chemicals, I´d describe influence as toxic and inspiration ephemeral."
Inspiration can be everything, a model pose, a wonderful song, a commercial, watching leafs on a tree, you name it. But influence is in an artists case almost comparable to a stamp, like an exquisite evening at the discotheque for example, however the stamp cannot be removed that easily and its also that important to know where you are coming from and heading towards as an artist.
Because that way you can leave the path, tryout things and come back to the roots at every time, but its definitely important to not just copy or learn from one person alone, exactly as it is in school to have different teachers who have different approaches in teaching things.
"influence-map" on deviantArt you can find in the artist-description something more relevant info´s about each artist in detail, while these are my roots, inspiration can take over and help me explore absolutely new paths and ways to redefine whats possible.
These are also just artistic influences, music and writing are nice too, but people behind all that and in general have an even bigger effect. I´d say even quotes have a big influence, well at least they help to keep the head up in tough times.
When it comes to mind-popping quotes or making the brain-bend, I highly suggest some inspiring words from Oscar Wilde, Bruce Lee, Steven Wright and Randy Pausch, below I´ll just post some that I find very thought-provoking.
There are for sure others that might be inspiring, please feel welcome to share your favorites as well! What quotes or authors would you put in big letters on your desktop wall?
Oscar Wilde: "Consistency is the last refuge of the unimaginative!"
Bruce Lee: "If you are being in critique, you have done something right, a player will only attack another one who has the ball."
If you have a look on deviantArt searching for "influence map" you´ll find a lot visual input and its clear that not one artist is without influence, it just depends if you "stick to your roots" or if you "branch out and explore", what type are you? I think I´m a little bit of both.