1. Contextlessness. Create an aura of mystery by presenting landscapes and events with no narrative context, or an ill-defined one in an archaic past. Perfectly ordinary events become enigmatic when they are deprived of context. "A man stopped in a clearing in the woods." Who was he? Where are those woods? It never matters very much because it is all symbolic anyway. Pseudo-reference is also good: the technique of referring to something as though your readers would know it: "The archers had exhausted their arrows." Vagueness of reference is an essential surrealist technique.
2. Dark and deep. Use words like these that suggest, by their very meanings, the mood you want to create. I wouldn't use the word "mystery" or "enigma" though. Anything evocative of profundity and darkness is good, like caverns or underwater passageways.
3. Landscape. Refer to non-existent landscapes. In my cheap surrealist poems I like to use qualifications like "skies of salt" or "mineral winds." Mineral, in fact, is a good all-purpose surrealist adjective, for anything not mineral: "your mineral gaze." "The days of mineral."
4. Pseudo-wisdom. You want to suggest that there is a profound, arcane wisdom to had in dark, mysterious caverns. Pretend you are listening to oracles.
5. Substances. I just add salt to everything to make a poem surrealist. "The days of salt and ash." Ash and chalk work well. (See mineral above.) Use the generic names of things: bird, reptile, rock, stone, skin. Vagueness creates mystery.
6. Animals. Animals are inherently surrealist because they possess a deep animal wisdom that we have forgotten. "In your animal darkness." Vegetation can be surrealist too.
7. Oneiric. Everything must happen as though in a dream, laden heavy with symbolic content.
8. Fable. Little absurdist surrealist fables are excellent: "A man was drinking his own blood. The mineral sky turned reflected seas of ash."
9. Prose poem. A good way to write surrealism is to do it in prose, especially if you doing oneiric fables with the pseudo-wisdom of animals.
10. Avoidance of everyday life. Try not to mention anything everyday in your surrealist poems. Everything most occur in that contextless dream land of caverns measureless to man.
11. Archaic. I've mentioned this before, and should really call it pseudo-archaic. Use words like "ancient" or "antique." What happens in your cheap surrealist poem could have happened 10,000 years ago.
12. Humor. You can be funny in a kind of absurdist, oneiric way, but not funny in a way that undercuts that mood by introducing elements from day-to-day life or otherwise breaking the mood.
There. Now you can write the cheap surrealist poem. You can combine these tips with good poem tricks and the bad poem tricks as well, depending on whether you want to write the good or bad cheap surrealist poem.