Hallo..
We have just had a game of cluedo with a couple of friends. The travel
version, in which everything is on small cards. We had a lot of fun.
It ended up in a friendly way as everybody won once.

I got muddled up with the sort of notes I should take and in the past
always wanted to develop a notation for the next time. Of course never
did, once the game was put away.

So, this time, I will get it and my question has two parts:

1. What bits of information should I gather? 
For example, I have to note (a) that I have cards x-y-z, (b) the cards
that I see from other players (with their names?, so I can avoid
asking the same questions over and over to the same people), (c) the
cards that player 1 asked for (which may imply that he does not have
them), and so on...

2. What is a practical notation for this purpose? The bits of paper
have 4-5 columns and are pretty small. For example, the first column
will be: cards that I saw and next to each card comes the letter of
the person I saw the card. Second column could be: player 1 does not
have this card. And so on...

I dont know how much everybody remembers the rules of the game off the
top of their heads right now. Please ask for clarification, if
interested.

I am more interested in discussing and developing a solution over the
discussion, rather than finding a prepared solution on a site.

Thanks, 

Can1972

In the US, Cluedo is called Clue.

can1972, I will wait and see if a real researcher answers your
question.  If no one does, I can give you a few tips from my own
experiences with the game.

It looks like I'm as good as you're going to get.  :)

You definitely want to take note of a) who has which cards and b) who
does not have which cards.  Those are definite pieces of information
that you can use to be certain about the answer.  I devote one column
to who has the cards.  I start by putting my initial next to the cards
I have.  When people show me a card, I put their initial next to that
card.

When someone doesn't have a card (this is information you can get even
when it's not your turn), make a note of it.  I generally note this by
putting the person's initial next to the card, in a different column
than I'm using to note who has the card.  Occasionally you'll hear in
a couple different turns that various people don't have the card, so
you can end up deducing that the card is in the envelope.

What people suggest on their turn can be informative, but this isn't
surefire information.  Probably they won't suggest 3 cards that they
have--that would be silly.  On the other hand, they might be trying to
force the other players to show them a specific card.  They might have
spent many turns trying to get to the ballroom, and so they don't want
to see somebody's weapon card when they finally get there--they want
to see the ballroom.  So they might use a person and weapon that they
have in their hand.  If you see someone going from room to room using
the same person and weapon, he's probably either holding those cards
in his hand or has decided that they're in the envelope.  Either way,
he's trying to get people to show him room cards.  I don't have a good
system for tracking this sort of thing.  I've tried writing it in the
margins, but the margins are pretty small.

That's about all I know right now.  If you come up with a good system
for noting what people suggest on their turns, let me know.  I have
occasionally gotten some info from my marginal notes.  (E.g., person A
suggests it was Mr. Green in the ballroom with the knife, and person B
shows A a card.  Later I find that B does not have the cards for Green
or ballroom, so therefore B must have the knife.)  However, my notes
often get to muddled that they're only good for the first couple
turns.  Maybe the solution is to use extra paper?  Or do the rules
prohibit this?

Hi biophysicist,
thanks for the tips. Another session is planned for the weekend. I
will use the opportunity to test these and will report some time soon,
I hope.
Take care,
Can1972