I think we can define some "novice rules" which can help at start....there is no easy way to guess what is the meaning of a ся-verb...
First of all "-ся" means that action is directed to subject in most of all cases.
Let's examine:
1. Reflexive: Он бреется. / "Он бреет" is "He shave something". wrong. So "-ся" is for "He is being shaved (by himself)".
2. Passive: Дом строится. / "Дом строит" is "House build something". wrong. So "-ся" is for "House is being built (by someone)"
3. Decausative: Мяч катится. / "Мяч катит" is "Ball rolls something" wrong. So "-ся" is for "Ball is being rolled (by process of moving / by nature / by nobody specific. So, just "ball is rolling")"
4. Self-Causative: Он бросился на врага. / "Он бросил" is "He throw something". wrong. So "-ся" is for "He is being throwed at the enemy (by himself)"
5. Reciprocal: Они целуются. -- / "They целуют" is "They kiss". not wrong, but "-ся" here is stand for "They kiss AND simultaneosly are being kissed (by each other)". Process is reciprocal by the nature.
6. Reflexive-Causative: Он подстригся у парикмахера. / Again "Он подстриг" is "He cut hair (of someone)". wrong. So "-ся" is for "His hair was cut".
7. Reflexive-Beneficial: Он запасся дровами. / Semiexception. Action is directed to subject, but translation is not as direct as above.
8. Objectless (so-called Middle Voice) : Эта собака кусается. / Exception!
9. Modal-Passive: Дверь не открывается. / "Дверь открывает" is "Door opens something". wrong. "-ся" is for "Do is opened (by someone)".
10. Impersonal-Passive: В работе на это указывается. -- Exception!
11. Impersonal-Modal-Passive: Мне не спится. / Semiexception. Action is directed to subject, but translation is not as direct as above.
So, it most cases they can at least expect that action is directed to subject. If this sounds strange - they should look for details.