▶ See = you just happened to see something.
▶ Look = you look at something for a reason.
▶ Watch = you look at something for a reason and carefully, usually because it is moving.
✔ 'Look', 'see' and 'watch' seem very similar, they all talk about different ways of using your eyes. However, there are two very important differences. It depends on how you intend to look or watch and how intense the looking is. When we say ✔ 'see' we are normally talking about things we can't avoid – so for example, "I opened the curtains and saw some birds outside." - I didn't intend to see them, it just happened. However, when we use the verb ✔ 'look', we're talking about seeing something with an intention. So, "this morning I looked at the newspaper" – I intended to see the newspaper.
When we ✔ watch something, we intend to look at it but we're also looking at it quite intensely, usually because it's moving. So, for example, "I watched the bus go through the traffic lights." "I watched the movie." We want to see it, we're looking at it intensely and it's normally moving.
When we use verbs of the senses, and this group, ✔ 'look', 'see' and ✔ 'watch' are verbs of visual sense, there's usually a difference between intention and non-intention, so, for example, "I heard the radio." - I didn't intend to, it just happened, or, "I listened to the radio" - I switched it on to find my favourite programme. Similarly, "I felt the wind on my face." - I didn't intend to feel this, it just happened, or "I touched the fabric." - I intended to feel the fabric.
Remember, ✔ 'see' – you didn't really intend to, it just happened; 'look' – you intended to do it; and watch you intended to do it and you were looking intensely, usually because it was moving.