One of the typical mistakes my students make is using the preposition "to" with the verb "arrive".
For example: *We arrived to London.
The preposition “to” can never follow the verb “arrive”, because it is a preposition of movement and the verb is not. Instead of “to”, we can use “at” or “in”, but, when should we use one or the other? The answer is easy:
- We use “at” when we get to a small place such as an airport, station or village.
- We use “in” when we get to a large place such as a country or a city.
Ex.: The Vikings arrived in Britain in the 8th century.
Sometimes it's not so easy and you can find examples like:
They arrived at Cardiff
Being Cardiff a big town, "in" should have been used, but "at" is correct because we actually mean arrive at Cardiff station or airport.

You can watch this video to help you.http://www.engvid.com/arrive-at-on-in/ or you can do the following exercises: http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-23122.php
