Some of the best advice I've found is here:
http://vimeo.com/20274994
Bowen is amazing.

Is there a general site that has scoring advice on several games?

The rules guides at pinball.org often have tips in them or a section of tips at the end.
http://www.pinball.org/rules/

The Bowen tutorial is AWESOME but TSPP is so complicated that even that won't really cover the entire game. Still, watch it a few times at least and you'll have a better idea how most of the game works. I watched it probably 3-4 times before I completely understood everything that was going on.

As for my strategy (similar to Bowen's really) I want to get a few TV modes going (garage > living room > mystery target > TV > couch) then start couch multiball. Hopefully during couch you can complete the shots required to get victory points. Also, Itchy and Scratchy multiball will often happen on it own once you get couch multiball going. If you can do all that in one ball and keep multiball going for at least a bit, you can score some pretty good points... probably in the 20-30M range. As an aside, in tournament mode, the mystery award will usually be light TV so you can rinse repeat this pattern to score big. This may be different based on the software version however. In standard mode, you have to shoot the Krusty (outside right) orbit to re-light the TV.

Otherwise, points are spread all over the place in TSPP so a good score can come from many different strategies. I think in tournament play, over 10M would probably be enough to win most of the time. But it really depends on the difficulty of the outlanes, so I would take a close look at them when you step up to the game as the left side posts can be set to barely allow a ball out or to allow almost everything out. The right side posts can be adjusted as well. The smaller the space back into the shooter lane, the easier it is to nudge balls out of that side.

Will the game be set to tournament mode or are extra balls allowed? If extra balls are allowed, I always try and go for Moe's ramp shots right away so that I can get a good start toward an extra ball at some point during the game. You'll get one at 10 loops on standard settings. Moe's is easy to backhand as well and it's generally a safer shot unless rollbacks are going SDTM. My TSPP typically rolls them back to the left flipper for an easy bounce-over and catch.

That is where I would send you as well emo.
The list is a 1/4 mile long!
It is funny with TSPP that just simply learning the rules helps immensely rather than just trying to stack the modes and flail about on the multiball- hey, even I am guilty of it!
Sometimes pinball should be pinball.
But in a tournament unless you are REALLY lucky, you will lose every time to the person (similar timed game) that knows the rules inside and out- VS. the "Flailer".
Good luck emo!
Don't be afraid to backhand Otto a bit (+Right orbit)...
Just keep that timer rollin'!

Edit: Good question Jay!
What are the Tournament guidelines emo?

I watched the video earlier.
Amazing stuff!!
Bowen is so nonchalant with his skills.
I can't hang with that guy...
Even a casual Bang-Back thrown in without stressing/breaking his commentary!
Worth the time!

He is one cool cucumber. The guy barely breaks a sweat, and yet he can kick almost anybody's a** on the planet.

It has been a while since I've played TSPP.There is one part of the game I do remember.At some point of the game you will go into a mode where the flippers wil be reversed.Right flipper button operates left flipper and left button the right.Almost impossible to keep the balls in play when this happens.I found that when this mode comes up I would cross my arms so my right hand is on the left flipper and left hand is on the right.This change makes play normal again.Worked great for me.

If you know nothing else about Simpsons, probably the best shot is the center/garage. It starts modes up top, leads to multi and the feed to the right flipper is safe. With limited time before the tournament, I would try to learn a basic stack around that shot.

In your warmup time, I would focus on the games you know reasonably well and not the games you don't know. No amount of warmup on unfamiliar games will make a win likely. Also, there's nothing more soul-crushing than wiping out on a game you know really well.

The scoring also comes into play. If the tourney uses a papa style scoring of 4-2-1-0, then what you want is FIRST! If you suck at simpsons and spend all your time warming up on it, maybe you go from 4th to 3rd as a result. One whole point. Likewise, because you didn't warm up on Addam's Family, which you know really well, you took 2nd instead of first. You gained one point but lost 2.

Congrats! So what was your winning score?

Emo, if you need some more practice on TSPP there is one in an arcade not too far from you. It's at Dawlish Warren, in an arcade next to the train station. I was down that way yesterday and had a few games on it. Unlike most arcade pins, this one plays really well, apart from a weak right lower flipper. I'll stick it in the locations page later.