Far as symbols go....I've heard more than one writer at readings or seminars respond to a question about a symbol by saying something like....no, in that particular case the symbol wasn't intentional, but sure it works that way and they wish they had thought of it consciously.
Exactly! It's possible to interpet a symbol differently than the artist intended. Or see a symbol the artist didn't intend at all. Or find a symbol not consciously intended by the artist, but maybe subconsciously. In my own writing, I sometimes go back over earlier drafts and think, wait a minute! There are lots of hotels and motels here, and they change over the years in much the way the family in the story changes over the years (real example). So in subsequent drafts I might try to emphasize that by tweaking the descriptions, strengthening the connections, using hotel-related analogy in places where I might otherwise use some other kind of analogy. In that case, maybe in many uses of symbolism, the idea started out in my subconscious -- and, because that particular piece happened to be a nonfiction essay, also in real life -- but was quite consciously developed afterward.
In doing this, I would try not to make the hotels stand out so obviously that the reader gets bonked in the head with A Symbol. And symbols probably shouldn't be things dragged in from outer space that wouldn't otherwise fit naturally into the context. Like, in Brokeback, fountain pens or champagne glasses wouldn't be good symbols (I started to say "roses," but then -- oops! they are!). To work well, symbols should be subtle, ideally entering the audience's unconscious the same way they emerged from the creator's unconscious.
But you can consciously find symbols become often they keep reappearing, or because they appear in contexts that are just slightly ... unusual. So coffee pots: Ennis is washing a coffee pot when he looks up with concern at Jack riding across the mountain. Ennis bangs on a coffee pot while Jack sings Water Walkin Jesus. Ennis sees a coffee pot and bucket when he opens the tent the morning after TS1 and looks out at his new world. Ennis says all the traveling he's done is around a coffee pot looking for the handle (colorful phrase, but strange). In the flashback, the camera pauses momentarily on a coffee pot and bucket, resting cozily side by side over the fire. In Ennis' trailer, a coffee pot is prominently set on his stove (sort of like the big fan on his bed).
Do any of these call attention to themselves? No (except, arguably, the traveling one). Do any seem artificially inserted in the movie to Mean Something? No. What to make of the scenes where Alma suggests Jack come in for coffee and when Mrs. Twist serves Ennis coffee and even when Ennis and Alma Jr. have coffee -- are those somehow related? Who knows. Maybe. Or maybe they're there just because Wyomingians drink coffee. Really good symbols, I think, are often a bit ambiguous and arguable and even abstract.
Could all of these coffee pot images be utterly coincidental and meaningless or just there to provide continuity? Not in my view. But if you prefer to see them that way, or if they don't work for you or enhance your appreciation of the movie, feel free to ignore them!
