If the kid is registered here in Switzerland, most likely, you're automatically getting the tax rebate for child support. Apart from the following tips, AFAIK, there isn't any tax rebate in Switzerland for employed persons.
- Declare yourself as agnostic, non-religious person so the local Church / Mosque / Temple doesn't take any cut from your paycheck.
- Get cheapest (and suitable) health insurance. Having everyone's insurance with same company may give you discount of 5-10% - depending on the insurer.
- AFAIK these won't help, but check with a tax expert anyway: declaring parents in home country as dependents, declaring any mortgages on property in home country, fringe benefits from employer viz. meals, trainings, books, SBB travel pass, mobile plan etc.