Practical - Now that is hard ^^
You see Socialism is a wild field and very unclearly defined, also changing through the times.
The Definition I "experienced" when I was a child is: S. is the step before communism.
The most commonly held basis is that S. is the socio-economic form after capitalism with social ownership (and democratic rule) of - and here comes the communist part - the means of production. That is Marx/Engels definition.
But as I said there are a wide range of definitions - hundreds - and as some include communism, others include anarchy.
You may be surprised by that, but don't forget that Marx/Engels also defined communism as "without ruler and classes" (while Socialism still has those, in "real existing socialism" countries even placed a lot of worth that you are from the worker class) - which is not far from anarchy ;)
tl;dr
The main difference is that Socialism still has a ruling class, Communism not.