Recognising types of reaction
Name a reaction by what happens: one substance splits apart, two join, a fuel burns, or an acid meets a base.
A worked example
2Na + Cl2 to 2NaCl is composition, because two elements join into one compound. CaCO3 to CaO + CO2 is decomposition.
The mistake people actually make
Count how many substances go in and how many come out rather than reading the names. Mass is conserved in all of these, so in a sealed container the products weigh exactly what the reactants did.