The high school kids around where I live, when they here me talk about politics usually end up asking what the difference is between Socialism and anything else, or why I refer to socialist as fascists.
It's not hard, it simply a matter of perspective. The primary difference between the four most common totalitarian philosophies is fairly simple. Who is the perceived owner of the means of production.
Communists - Make no bones about it - the state owns it all. This described the Soviet Union quite well. It also described China until they saw what happened to the Soviet Union. After which they "embraced" capitalism. They don't actually embrace capitalism, they are using it as a tool to build a military prior to resuming their state economy in a more world wide fashion. Oh and they're happy to build the bank accounts of the party elites in the process.
Socialists - Give the impression that private individuals own some of the means of production, and the state owns others. The fact that they regularly eliminate that ownership with a bullet should indicate who really owns the property. Just try not paying your (lease) taxes and you'll understand right away. Off to the deep dark hole you go, were you'll either work to death, starve to death or maybe they'll be nice and just shoot you after you've been forgotten.
Democratic Socialists - They try not to openly own any means of production - again just try not paying your lease (taxes) and you'll see just how secure your ownership really is - you'll find your business has a new owner and you have a new residence - a deep dark hole somewhere.
Fascists are somewhere between Socialists and Democratic socialists but rather than tossing you in a deep dark hole, the just put a hole in your head when you disagree.
So, the only real difference is what sort of public face they put on their totalitarian economy, and perhaps how quick they are to pull the trigger to make their point.