I think I've looked everywhere I could, but I couldn't find any dictionary where the difference between "to target at/on/for/towards" would be explained. Can you please fill me in as to how they are used? I need to explain it to a student and say more than just... "you'll know what to use" :)
Perhaps I am missing the point, but 'Target' as a verb is usually used without a preposition following it. As in:
'Let's target a 50% increase in sales this year'.
The use of 'Aim' would include a preposition, as in:
'Let's aim for a 50% increase in sales this year'.
As far as use is concerned (which wasn't the question, but I think it's relevant), 'Target' is less used as a verb than 'Aim', but it's not unknown. Ngram gives the following result for the search 'let's target, let's aim'. I considered searching for 'to target, to aim', but I think the results were skewed by such phrases as 'missile time to target'.
Testing 'We'll aim, We'll target' gave the following results:
I can easily use "to target on" in a sentence, but come up empty trying to think of an instance where one would use "to target at", "to target for", or "to target towards". Is it because use of the word target as a verb means the same as shoot toward? If that is the case, then we place a target "on" where we wish to shoot or focus our aim. Thus "to target on" means to place a target on a goal... and the other prepositions don't do this. However, in trying to make a sentence with "target" as a verb and "on" may be wrong too. Consider,
1. "this year we will place a target on increasing sales" vs.
2. "this year we will target on increasing sales" vs.
3. "this year we will target increasing sales".
The first usage target is a noun, the second usage "on" goes with "increasing", not with "target", and there is no "on" in the third.