Boy, being environmentally responsible is a topic full of facts, fiction, passion, misinformation, and philosophy!

Narrowing things a bit, you're asking mostly about "front country" camping rather than "back country" camping, specifically about garbage and rubbish. Leave No Trace (LNT) is probably the most widely accepted practical approach to that sort of thing. Here is a link for the teacher in you: http://tinyurl.com/ge9ve

Here's the main site: http://www.lnt.org

I suggest getting a handle on the back country ethos of LNT first, then understand the front country application of that approach.

My 2 cents, setting aside all sorts of philosophical daily living types of discussion:

It starts with your trip planning - for example, I do not like including MREs in the menu for backpacking simply because they are extremely trash intensive. OTOH, as a practical matter, I usually have one or two in my Ready Pack and if I'm heading out for an impulsive day trip, sometimes I'll toss one in for lunch (usually not, but sometimes).

If I have a campfire in an established campfire site, I usually will burn paper and paper products. I almost never burn garbage (food bits), plastic, or metal (most envelopes/pouches have a foil and/or plastic liner). There have been exceptions, and I do my absoute best to get ever scrap of residue picked up and packed out for better disposal. If I have a fire in a back country setting, nowadays I usually don't put any residue in the fire. It's not a perfect world.

I find it useful to keep 2 - 4 thin plastic grocery sacks stuffed in my kit even for day trips. It's amazing how much better folks are at picking up after themselves if they have a sack to put things in (double bag and tie on the outside, usually) And the sacks are useful for other things, too.

It takes real effort to not be pigs out camping, but every little improvement helps. I suggest learning LNT practices, setting a good example, and not turning into a zealot about it.

HTH,

Tom