Advice for a long time DM playing a game for the first time in a couple years?

[MonkeySage]

I'm playing in a pathfinder campaign for the first time in a couple of years, playing a type of character I'm not accustomed to on top of that.
First of all, he's a rogue- and I'm so used to playing mages.

My character is a lawful neutral halfling rogue, with very close family ties with the kids he grew up with at his old orphanage. When the orphanage was burned down, his brothers and sisters escaped with him, but his matron died in the fire.

The fire was no accident, and a year later my character managed to track down the one responsible and carried out his first assassination.

Since then, my character has sworn to protect the weak from those who abuse their power. He uses his skills to assassinate people like the man responsible for burning down his home, to keep them from causing more harm. He follows a strict code, which among other things dictates that he should never intentionally bring harm to an innocent person.

The kinds of people that he goes after are often the same kinds of people that a paladin would likely agree should be destroyed. Tyrants, slavers, warlords... The kinds of people that are beyond the reach of the law. The main difference is that his tactics involve stealth, subterfuge, and occasionally poison. (This is why I started him out as lawful neutral, not lawful good. I'm not sure if the rest of his actions qualify him as lawful good, at least not yet.)

When not on a job, the character does what he can to help out the same types of people he's sworn to protect. He won't skulk in a corner; like any good halfling, he'll mingle and carouse with others.

He's also fairly young, and the events that lead to him becoming an assassin are still a few years fresh.

In the party, I intend to have him play a supportive role- as party rogue he'll still be disabling traps, dismantling robots (which considering the campaign setting, robots are a very common enemy). His decent charisma means he can play the role of a party face, though our healer/off-tank is a charisma caster.

In combat, he's does mostly melee- dual wielding short swords.

I have a lot of ideas for what this character is like, but roleplaying him is another story. That's what I'm asking for advice on.