[Manuela]

The only pronunciation rule I get my students to remember is

Pronounce -id after verbs ended in in -t and -d.

It is quite difficult to pronounce the others incorrectly. And it is difficult to remember lists of sounds, as well.
Some sounds have voice (+voice) and some others haven't (-voice).

+voice -voice
b p
v f
z s
g k
d t
If a verb ends in a +voice sound -ed will be pronounced "d"(+voice)
If a verb ends in a - voice sound -ed will be pronounced "t"(-voice)

Try reading stopped as "stopd" or robbed as "robt" and you'll see that it is very difficult to do so. I explain to my students about the +voice - voice sounds and then tell them to just read the past tense as t or d, as it comes. However , they should watch out for the verbs ended in -t or -d. There it is necessary to add -id because otherwise we wouldn't be able to hear the past tense. How would wanted sound if we didn't read it as "wantid "? "Wantt"?