You ought to read some Bernstein(father of modern social-democracy) and Herbert (socialist philosopher from the US)
It's also good to read some critics on Marx, because it's always good to critize your own opinion. If not to temper your own opinion, it's also good to prepare for eventual counter-arguments by others. For that, read Max Weber (famous sociologist) who said Marx' oversimplified the class-struggles. Sociology is important in socialism to understand the struggles, so definitely also read Emile Durkheim
Besides that, read up about the OctoberRevolutions in 1917 in Russia, the November Revolutions in Germany in 1917 and etc etc. Learning your history is extremely important.
I'd also suggest remembering things like these capitalist failures or like this show with John Oliver adressing how tobbaco companies sue nations for anti-tobacco laws
If you really want a good basis for socialism, you need to know your statistics as well. Know your average unemployment rate, look up scandals like the Luxleaks or Swissleaks, look up the debts, look up all kinds of things.
You're going to be in a lot of arguments, so you'll need to be able to smack them in the face with facts and sociologists and philosophers and all that. I recommend that above certain books who are mainly focussed on "inciting" socialism in people, because you can't use those in arguments.
Most of learn, build up constructive criticism even when you yourself are argueing. Recognise the flaws of your ideology, because if you recognise them but for example offer a solution or example, you take away a weapon from the non-socialists.
TL;DR: Check the links and learn your statistics.