Hi, I´m new!

[DarkFish]

Usually we welcome new people at subsim with "Welcome Aboard", but to a fellow Dutchman I'd rather say:
Welkom aan boord

As for your questions:

1: Am I missing some "must have" mods? (I've seen some of your screenshots and they still are a lot better than mine..)

Not that I know of, TMO already includes some graphics mods. There are other supermods out there though, some of which include graphic mods that may be more to your liking.

2: Witch mission(s) is/are best to play first as a complete noob?

I'd say campaign. The missions are all hard for a complete noob i guess, they all include some huge, heavily escorted convoy or taskforce, you won't find lone shipping in the single missions.