Mixtures are created using two or more chemical substances. If all the substances in the mixture are in the same phase, i.e. solid, liquid or gas it is a homogenous mixture, else if two substances that differ in phase form the mixture it is a heterogeneous mixture.
If the freshly squeezed lemonade is made by squeezing lemons to extract the sour juice and mixing this with water and sugar all the substances in the mixture finally created are in the same phase. This makes the lemonade a homogenous mixture. In case the lemon juice is not filtered properly and contains pulp or seed the resultant mixture would be a heterogeneous one.