The key feature to remember about druids, from any setting, is that their key two tenets are the following:
Uphold the Balance
Protect NatureUpholding the BalanceDruids believe that the forces of Good, Evil, Law, and Chaos are all equally relevant to the functioning of the cosmos. When any of these grows more powerful than its opposing force, the druids will carefully consider the situation, and if deemed necessary, they will aid the "losing" force to the extent that balance is somewhat restored. For example, if Lawfulness is bordering on tyranny, and individualism is being threatened on a mass scale, they will work to promote chaos until a balance is somewhat restored, and vice versa. If Evil is growing in great power and threatening to overwhelm good, they will aid the forces of good until such a time as things are more evenly balances, and vice versa. Thus, a druid who willfully neglects to pay attention to the Balance, or who works to swing things in an even more lopsided direction, could lose druid powers. For example, the nearby lands are dominated by an ultra lawful cabal of rulers, who are oppressing all and sundry in the area. If a druid then works to maintain the status quo by enforcing the laws, or say, joining forces with the ruling powers, they would lose druid powers. If they did the exact same actions in an area fraught with anarchy, they would be maintaining the balance, as per their oaths. This ever-changing nature of these four extremes is why druids are always neutral in some way, hard to make friends with larger agencies because one day their efforts might benefit a particular party, but weeks from now the Balance calls for something else.
Protecting NatureDruids are charged with being the defenders of Nature, and swear to protect nature when they become a druid. This does not necessarily mean slaying people out hunting for food, or clearing wildlands to grow crops. Whereas certain more psychotic druids may very well take this stance, it is not the norm. Druids generally oppose damaging the natural world for unnatural reasons. Hunting for food is natural. Hunting for skins to sell and make a profit trading them is not. Clearing land to grow crops is natural. Razing the land as an act of war is not. Likewise, druids will enable no callous harm to animals. Thus, they will oppose casual slaughter, torture, or any unnatural act forced upon an animal (such as being forced to fight in cage event, or even taken out of it's environment to serve as prowling attack creature in an estate). This extends to their own animal companions, who are considered equal beings to the druid, and often their closest friends. A druid who neglects to protect the natural world, or does something to actively harm it, will no longer be considered a druid.
And their other oaths and concepts Druids may not wear metal armor or shield, or brandish non-druidic metal weaponry. (Druids wouldn't weapons that are clearly weapons of war, but rather, conventional tools that 'may' be used as weapons.)
Druids may not take up permanent residence in a city, castle, temple, etc, as this is considered a concession to the unnatural world.
A druid may not teach the secrets of the druidic Order and/or their own Circle, to any non-druid. Be mindful of this, druids do not cast verbal components of spells in druidic. The nature of the language is often extreme-metaphors, anyways!
When Druids take their oath, they are expected to respect the traditional structure of druidic society. Simply put, there is typically one Great Druid leading a circle, which oversees a large portion of land. Issues such as band and edicts, are often voted on by the entire Circle, with majority decision being the verdict. As such, even if a druid is a loner who refuses to partake of the Circle's meetings, the druidic fellowship is expected to be respected by all who have taken druidic oaths.
As far as some of the concepts in discussion, what people/druids eat is merely a matter of personal character, not a tenet of druidism. The acts of cutting trees, hunting animals, and wearing leather is certainly allowed, but the motivations behind them is where druidic morals apply. You can feed yourself, make tools and clothes to survive. You can't open up Druids-R-Us and slaughter animals and forests for profit. The very nature of gold and economy is an abstract concept for a druid to participate in.