Prepositions are famously difficult to learn in English. It is something that most people have trouble with. It doesn't matter if your first language is Italian or Japanese, you probably find prepositions very frustrating. However, most people learning English don't even know what prepositions are, what they do, and how to learn them.
Prepositions don't mean anything (kind of)
Prepositions are always used with nouns and verbs. When they are together with some other words, then they really mean something. To native speakers, "for" means "for". You cannot get simpler than that. To explain what a preposition means by itself takes a lot of words. Go ahead and look at "for" in the Oxford English Dictionary. Good luck reading all of that!
Can you think of other words like this we use for grammar? Ask me in the comments if you are not sure.
To understand this point better, you need to know that there are two kinds of words in languages: words that mean something and words that are used for grammar and structure. Nouns, adjectives, adverbs and verbs are used to communicate meaning; auxiliary verbs, articles and prepositions are used for structure.
You can easily understand if a word is used for meaning or grammar with a simple test: Can this word be a one word sentence?
For example, if I suddenly shout, "Lion!" it means something — a big, angry cat. If I then yell, "Run!" then you know what to do. Words like "lion" or "run" are used to communicate meaning. But what if I said to you, "Can!" What then? Or, "At!" You would think I am a crazy person. Prepositions are words that are basically meaningless unless they are used in a phrase.
Prepositions are used in two ways
In English, prepositions are used in more or less in two ways:
- before something; and
- after something.
Prepositions come before things in prepositional phrases — something like "to the bank" or "for my sister". Prepositions come after verbs and adjectives with things called a prepositional object — "look at the bird" or "listen to music" — and adjective phrases, like "happy with" and "good at".
Prepositions are called "prepositions" because they usually come before something. If you are a Japanese speaker, then you use postpositions, which come after the word they relate to. A simple example: 駅へ = to the station. So what? That means that you have to think backwards!
Prepositions are always used in phrases
This is really just saying the first two things again, but you have to understand it — prepositions are never alone, so never learn them alone. Always learn prepositions as part of a phrase.
Prepositions are basically about space
Prepositions are used to explain relationships between things. They communicate relationships in space. That spatial image is then used metaphorically to create an image. You write on paper with a pen, because the words are literally on the paper. That image is used when we say, "I saw a movie on TV." Sometimes, and only sometimes, you can see the image behind the preposition.
Prepositions are really tough
Please accept that prepositions are really difficult. Korean has something like 12 post-positions. Japanese has a little more than 60 particles (and some of those are combos, like のに and ので. English has at least 150 prepositions in common usage. And when some of them are like "for" and have pages and pages and pages written about them in dictionaries, you know that it is going to be a challenge to learn them.
There is no short cut
I wish there was an easy way. It would make my job a lot easier, and you would have more time for hobbies and family. But there is no short cut. If you want to learn prepositions, you have to be patient and expect it will take a lot of time and effort. You also have to realise that in many cases, it is just a case of pure memory power. You either remember them or you don't.
You cannot translate prepositions
Because there are so many prepositions, and because they are so complex, do not expect that there will be a nice one-to-one relationship between an English preposition and one word in your native language. This is where students make big mistakes.
I once had a student who thought that "for" was ～のため, and it is... sometimes. She could not understand "train for Shinjuku" or "I stayed for ten days". She would look at me in the class and say, 「新宿のための電車？？？」 and 「十日のため？？？」.
Don't make that mistake. Be flexible in your thinking and use your imagination.
There is no perfect
You can get really, really close to mastering prepositions if you try. Realising that this is one of the most difficult things to master in English should help you to relax about it. Take your time.
Unless you are a native speaker, or you plan on living in London for the rest of your life, you will probably never be perfect with prepositions. There will always be something that you get wrong. But trying to be perfect with prepositions is like me wanting to win Wimbledon if I just started playing tennis last week! After all, mistakes with prepositions is one of the ways that native speakers can tell if someone who is very good at English is not a native speaker.
Prepositions don't really matter
The last thing to know is that using the wrong prepositions rarely matters. Most of the time, native speakers know what you mean. There is an obvious difference between something being on the table and under it. I don't mean that sort of thing. I mean the more difficult cases. If you said you read a story by the newspaper, I would still know what you mean (it's "in the newspaper", by the way). That doesn't mean you shouldn't care. It just means you don't have to worry about your mistakes. 99% of the time, they won't matter.
If you are super-keen and enthusiastic to win the war against prepositions, a good place to start is by getting this free ebook of prepositions in English and examples. Keep in mind the 9 points above, and one day I promise, with patience and energy, you will have no trouble with prepositions at all.