Please help me guys, I can´t seem to understand the -miş suffix.

I don´t understand when is it necessarily used and what does it mean although I´ve read tons of lessons about it. It still won´t get inside my head.

Hey,

I´m not a native speaker, but when I learnt this tense, I was explained that it is used with regards to information that you haven´t actually seen yourself. For instance, you say that someone has arrived to the city, because you heard he had, but you didn´t see him yet r with youown eyes, so you use -miş. So it is used with doubt, possibility, uncertainty, probability and cases like that.

So I always apply it in past sentences where I´m not sure of what I´m speaking

Maybe turkish native speakers will correct me.. 

if you have personally witnessed sth, use "-di" past tense.
if you havent personally witnessed sth but heard it from someone else, use "-miş" past tense.

For example:

kaza oldu.
there was an accient. (i was there, i saw it or i just came there after the accident.)

kaza olmuş. there was an accient.
(i heard that there was an accient, heard it from tv or from a friend... i havent personally see the accient or its signs afterwards.)

m.

Apart from its usage for reported past , it can be also be used in the cases as follows : 

-miş can be used to express amazement, admiration,suprise and things that you have just realized. Such as:

 When you see your friend´s car first time and you like it, you can say to him/her :

- Araban çok güzelmiş ! ---> Your car looks very nice !

 You are viewing a house and you find its rooms  big , you can say :

- Odalar genişmiş !  ---> The rooms are big !

- Bak kim gelmiş ! ---> Look who has come !

Your friend bought new shoes and you think they are good deal :

- Ucuzmuş !  ---> They are cheap ! [good deal !]

You´ve just started to learn Turkish and you find Turkish difficult. You say to your friend

Türkçe zor bir dilmiş ! ---> [I have just realized that ] Turkish is a difficult language !

Sabah olmuş ! --> We [I] have just realized that it is [the night turned into] morning.