French

[TheYESDragon]

Isn't dans usually used more when referring to a time in the future (for example, dans le futur) or referring to a place you would be in (for example, il est dans le maison) while en is used more when referring to an action in the present tense?

After a month since I did French GCSE, I can't remember much more though xD

inb4 Sunny comes along and shreks us all with her francais skills

 

[Hayleia]

Je me suis or je suis

"Je suis" is just "I am".
"Je me suis" can happen in two cases (or at least, from what I see).
Example one, "I bought myself a game" gives "Je me suis acheté un jeu", where the "me" comes from the "myself".
Example two, "Je me suis trompé(e)", and this is just because the verb is "se tromper", not just "tromper".

Dans or En

As @TheYESDragon said, "dans" works for places. "In the drawer" is "Dans le tiroir". It can also be used for the futur, yes, but also for the past in "dans le futur" and "dans le passé", probably because it's not really defined. You're not giving a date. And when you give a relative date, it works too, like "in five minutes (from now on)" which is "dans 5 minutes (à partir de maintenant)" in French.
"En" is more for absolute dates I'd say. Like "in 2015" which gives "en 2015". Or "in this moment" which is "en ce moment". Or "in january" which gives "en janvier". And past or futur, same. Just don't use it with days (but even in English it's not the same, you say "On Monday", not "In Monday", and you just translate it into "Lundi" in French).

But maybe you'll find some very old texts in English that say "en le tiroir" instead of the usual "dans le tiroir", and don't worry, it seems weird for French people too

On or Nous

First, the official distinction
Basically, "nous" is defined people. When you're with friends, you say "nous" to tell about your friends and you.
But "on" is undefined or general. Like when you say "my bag has been stolen", you can translate it into "mo sac a été volé" but it's more usual to see "on m'a volé mon sac". Like that "on" people stole your bag, you don't know who they are but someone stole your bag and you call them "on", someone generic.

Now, the unofficial use
All of the above still applies, but French people often use "on" instead of "nous" (and not the contrary). So you can do what's said above or use "on" everytime and it should work
You'll basically replace "nous" with "on" in casual places, like when talking orally. And on the contrary, when writing a formal essay about your day (for some reason), you'll say "nous" to talk about you and your friends.
(Except that you only replace "nous" with "on" when it's a subject, when it's translated into "we", not when it's translated into "us").