I took a couple of pictures of various aircraft and I would like to know which aircraft I photographed. I have no idea, expect that all of them took off from ZRH and should be commercial airliners:
One of the simplest things you can do is to type in the registration into Google which will normally give you results of the type and history of the aircraft.
Otherwise, many airlines don't operate too many types of aircraft so a quick look on Wikipedia and looking through 'fleet' should show you which types it may be, from which elimination should be pretty quick.
The registration is normally visible on the back of the fuselage and under the wing (D-ABEP on the rear fuselage below), and the last two letters are (often) printed on the aircraft 'forehead' above the cockpit windows, the top of the tail and the nose gear doors (EP on the nose gear doors below).
Aircraft from your photos:
The accepted answer has good advice. I would add that a quick and easy way to make a guess at the manufacturer is to look at the ends of the wings. Notice how in the first picture the wings "bend up" at the end. This is highly characteristic of Boeing 737s.
By contrast, the "fence" style wing tip that you see in three of your photos is highly characteristic of Airbus.
See Wikipedia's article on the matter for more information about why wings have unusual tips.