Throw away less food

I totally agree with throwing away less food. In Australia, we say expiry date rather than sell-by date, but I'm not sure if that's what they say elsewhere.

You always make a list, not do a list. When you make a list, the preposition after it will be 'of'.

You always go shopping, not do. These can be tricky to remember, and I'm not sure of a rule. Unfortunately they are just to be memorised.

With the verb 'to look', the preposition you use depends on the situation:

At is most common. Look at me. Look at the car.

Sometimes you use 'in' when you specifically mean 'look in the box'. If you say 'look at the box', it means you are looking at it from a distance, and not what is inside.

Occasionally you also say 'look over there' or 'look here'. In these situations, you don't use 'at'.

Throw away less food.

When I do the shopping, before going, I make a list of the products that I need and I only buy (the)* necessary things, and I look closely at the sell-by date and I check if it’s near.

Well done  José.

I agree with Kevins comments. However, here in the UK it is usual to say 'When I do the shopping' when we are going to buy the daily essentials like food. To say - I am going shopping - is less specific and can include any type of product.

* Optional