As a new Swiss citizen, starting this month I am doing my own taxes.... for the first time in my life.

I've asked for some advice from my Swiss co-workers, but I have a feeling that they've been doing it so long that they can't quite explain it to a beginner.

Lots of people on this forum must have found themselves in this situation and I would just like some pointers. If an older thread exists, please direct me towards it, because I couldn't find one.

From what I've been told:

-If I'm 25 years old and single, I shouldn't count on too much being deductible. Basically, the rate they offer is the one I'm going to get. Is this true?
-Are things like dentist costs and my yearly bus pass deductible? Is it worth it in the end? How much money am I looking to save if I keep track of these things religiously?

Geneva has an online version of their tax program now, so I'll play around with that.

Any suggestions, experiences, etc. are welcome! Thanks in advance.