machen vs. tun

Cecilia asked us a tought question: What is the difference betweeb the verb tun and machen, and how do we use them? Well, don´t like to dissapoint you, but there is no general rule for that. In most cases we can say:

tun = to do
machen = to make

But let´s see some examples. There are some sentences where you can use both verbs, so they are interchangeable, or in other words synonyms.

Was soll ich machen? = Was soll ich tun? = What am I supposed to do?
Ich habe nichts getan = I habe das nicht gemacht = I did nothing

tun = to do an activity, to put, to realize, to place

Es tut mir Leid = I´m sorry.
Es hat nichts damit zu tun. = It has nothing to do with it.
Er tut nur so = He is just pretending.
Das tut mir weh! = This hurts.
Tu doch etwas! = Do something!

Hint: Learn German idioms the way they are (with their mostly fixed words and order)

You can also use "tun" with nominalized adjectives:

Wir wollen immer Gutes tun. = We always want to do good.
Ich will nichts Verbotenes tun.= I don´t want to do anything forbidden.

machen= to prepare, to produce, to create

Heute mache ich Pizza = Today I will prepare a pizza.
Was machst Du beruflich? = What do you do for a living?

Mach bitte das Licht an! = Please turn the lights on.

Whenever you are talking about creating something you can only use make.

Hast du das selbstgemacht? = Have you made that on your own?
Hast du deine Hausaufgaben schon gemacht? = Did you already do your homework?

Some more expressions:

Drei und vier macht sieben = 3+4 is 7
Das macht nichts = It doesn´t matter.
Du machst mir Angst! = You're frightening me!
Das macht... hungrig/durstig/müde/fit.= That makes you... hungry/thirsty/tired/fit.
Do not use the verb tun together with another verb like in this sentence, because it is not gramatically correct. (Although you might hear someone still speak this way)

x Ich tue das Buch lesen. (I´m doing reading the book - I am reading the book)

And finally an idiom that you maybe already heared of:
„Hilf mir, es selbst zu tun!“ (Maria Montessori) = Help me so I can do it myself.

Mach's gut!= So long!/Take it easy!