How do you do mass to mass stoichiometry problems?

I'm assuming you mean reacting masses - for example:
"Calculate the amount of #CO_2# formed when 58g of #CaCO_3# decomposes."

So first you need to write a balanced equation:
#CaCO_3 -> CaO + CO_2#

Then you need to divide the mass you are given by its molar mass, to find the number of moles that react, so..
Molar mass #CaCO_3# = 40 + 12 + (3 x 16) = 100
Moles of #CaCO_3# reacting = 58g / 100 = 0.58

Then you need to multiply the number of moles of #CaCO_3# by the molar mass of the thing you have to find (#CO_2#) so...
Molar mass #CO_2# = 12 + (1 x 16) = 44
Mass #CO_2# = 0.58 x 44 = 25.5g.

If you have different stoichiometric ratios, it is simplest to multiply the molar mass by the coefficient first, so if you had a question, "Calculate the mass of #Fe_2O_3# formed when 10.0g of Oxygen reacts with excess iron"...

First write that balanced equation:
#4Fe + 3 O_2 -> 2 Fe_2O_3#

Then divide the moles of #O_2# given by the molar mass x 3, so...
Molar mass #O_2# = 2 x 16 = 32
Moles = 10 / (32 x 3) = 0.10417

Then multiply this number by the mass of #2 Fe_2O_3#:
Molar mass #Fe_2O_3# = (2 x 56) + (3 x 16) = 160
Mass #Fe_2O_3# formed = (160 x 2) x 0.10417 = 33.3g