If you plan to travel using Swiss trains (and I would recommend this) then you could consider buying something called a 'halb-tax' before you purchase any tickets.
It costs around 200chf (that might be a year or so out of date) but once you have it you can purchase train tickets - first or second class - at half price.
So, for example, a trip from Zurich to Milan in first-class would drop from around 300 to 150 chf.
So, if you plan to travel, say, more than three times it pays for itself. I have another tip of a similar nature: Swiss trains are a lot cleaner, newer and better serviced than Italian ones, so if you are travelling from Switzerland to Italy (which is a great journey) then either ask at the ticket counter who is the operator, try to get 'SBB' trains (the Swiss ones) rather than TrenItalia.
Another good operator is CISAlpino which I believe is some kind of joint operation.
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