没 negates past actions (我没去 = I didn't go) and 有 (我没有钱 = I don't have money). Use 不 for habits, preferences, and future actions (我不去 = I won't go / I don't go).
mistakes
Never use 没 with adjectives. Say 不高 (not tall), not 没高. And never combine 没 with 了: say 我没去 (I didn't go), not 我没去了.
