I find, I feel: thấy + adjective or sentence

Thấy means "see", and it also says how something seems to you. Before a describing word, it's how you feel: Em thấy hơi mệt. I feel a bit tired. Dạo này anh thấy khỏe hơn chưa? Are you feeling better these days?

Before a whole sentence, it gives your impression, like "I find" or "I think": Em thấy phim này hay. I think this film is good. To ask someone's view, say Anh thấy sao? What do you think? (in Hà Nội, thế nào).

English speakers reach for nghĩ (think) here. Nghĩ is for an opinion you've reasoned out, or a guess: Em nghĩ là mai trời mưa. I think it'll rain tomorrow. For your reaction to something you've seen, tried or tasted, thấy is the natural word: Em thấy món này hơi mặn. I find this a bit salty.

Cảm thấy means the same for feelings and sounds more careful; it's common in writing: Tôi cảm thấy rất vui.

Có vẻ (it looks) and hình như (it seems) are less sure: they report how things look or what you've heard. Thấy gives your own impression.

For seeing and hearing, thấy often goes after nhìn or nghe: nhìn thấy, nghe thấy.