Quote Originally Posted by RedFox View Post
Normally, a russian sentence has structure topic + comment:
Я уезжаю в Москву завтра. - "я" is a topic (i.e. what is your sentence about) and "уезжаю в Москву завтра" is a comment (i.e. information your sentence provides).

You cannot omit a pronoun if it is in the comment:
Завтра в Москву уезжаю я. (а не кто-то другой) - in this sentence, "я" is the main information, so it cannot be dropped.
both Уезжаю в Москву завтра. and Завтра в Москву уезжаю. without the "Я" sound pretty good to me.



Quote Originally Posted by RedFox View Post
When you have no context (i.e. just starting conversation) or change topic, you should keep a pronoun:
Я пойду купаться в озере, ты идешь со мной? - "Я пойду" - the beginning of the conversation; "ты идешь" - the topic changed.
Пойду купаться в озере, ты идешь со мной? also sounds ok to me. ЧЯДН?

Quote Originally Posted by RedFox View Post
So, in general... when in doubt, don't drop a pronoun.