There's some confusion between different ways to say "try":
- 시도하다
- 노력하다
- ~려고 하다
- ~어/아 보다
Are they used differently, or are the interchangeable?
They are not all interchangeable, and have somewhat different meanings.
"He attempted suicide" ("He tried to kill himself.") => 자살을 시도했어요
"I tried, but it didn't work out" => 노력했는데 안 됐어요.
"He tried to kill me!" => 저를 죽이려고 했어요!
"Have you tried (eating) Kimchi?" => 김치 먹어 봤어요?
시도하다 : 試圖 + 하다, more formal version of '아/어 보다'.
~아/어 보다 : literal meaning is "see(보다) what happen". I don't think this phrase implies trying or planning.
~려고 하다 : interchangeable with "~할 계획이다". Meaning one has a plan, intentions, or a goal.
c.f. "노력하다" is most popular (and almost exact counterpart) word for "trying (with effort)".