Sideboard for my Meta

[Brizzle]

Hello everyone,
I'm new to vintage (only played in one tournament and did pretty poorly).  I was hoping for some tips on a sideboard for my metagame.  I play ICBM oath, and currently, my SB looks like this:

2x SSS
3x Stifle
1x Darkblast
2x Pithing Needle
1x Rushing River
3x Tormod's Crypt
3x Arcane Laboratory

The tournament I played in wasn't to big (only about 20 players), but what I encountered was this:
A few Dragon decks, a few stacks, quite a few combos (Doomsday and Grimlong), and a lot of CS (made up half of the top 8).  For sure, I didn't see all that my area has to offer, but I would like to get some advice on what would be good in the sideboard against what I am seeing.  I believe that ICBM Oath is supposed to have a good match up against CS, but I blame the poor performance on my novice play skills in Type 1. 

Any advice would be great,
Thanks in advance.

[Jacob Orlove]

How are you sideboarding those cards? If you're taking the wrong stuff out, then it doesn't really matter what's in your board.

[Brizzle]

Well, I'm sure I probably made many wrong decisions (also, this current board wasn't the one I used, as I went in having no idea what to expect), due to my inexperience, but I found myself boarding in Stifle quite often.  However, I wasn't sure what to take out to make room.  I let Mana Drain take the fall most of the time, but I don't think that was the right decision.  I also found myself never drawing Null Rod when I needed it most.  Maybe another in the board is in order?