Moj dan

ki vs. kateri: in that case kateri is used only after a preposition.

Examples:

V kino me je povabil prijatelj, ki res rad gleda filme.
V kino me je povabil prijatelj, na katerega sem se ravno spomnil.
V kino me je povabil prijatelj, s katerim se že dolgo nisem videl.

delati: to make, to work
početi: to do something

svoj vs moj:
Svoj (povratni svojilni zaimek) is used, when the property refers to the subject.
Examples:

Tina se je srečala s svojimi prijatelji. (Tina has met with her friends.)
Tina se je srečala z mojimi prijatelji. (Tina has met with my friends.)
Tina se je srečala z njenimi prijatelji. (Tina has met with her friends. But in that case this friends are somebody else, for instance Nina's friends.)

and

Srečal sem se s svojimi prijatelji. (I met with my friends.)
Srečal sem se s prijatelji. (svoj isn't necessary because it is obvious that they are my friends.)
To so moji prijatelji. (This are my friends. They are the same people as in the example above, but in this case to is the subject.)

Don't worry, also the native speakers have a lot of problems with this!

-om/-em ending: -em is used only after a letters (sound) c, j, č, ž, and š.
Examples: z zmajem, z vencem, z bičem.

Moj dan

Moj vsak (Vsak moj) dan izgleda drugače, ampak so tudi stvari, kateri delujem dnevno (doesn´t make sense). Vstanem ob devetih in pojem zajtrk. Kdaj lahko, grem v kavarno (if you wanted to say that you go there when you can, you should have written: "Ko lahko"). Potem grem na univerzo in študiram. Popoldne berem knjige ali gledam televizijo. Zvečer se srečam s z mojimi prijateljami ali mojim fantem. Včasih rada grem  (grem rada) na bazen.