Try to talk to EVERYONE. Every NPC in a new place and each time if you return to that place, there are a ton of side quests you only get from talking to people! Talk to every Crew member after every mission, even sidequests! That's how you get info about their backstory and also unlocks quests that involve their personal story lines!

The first game is a bit more narrow on your "Nice" (paragon) and "Aggressive" (Renegade) dialog choices. By this I mean you'll need to try to stick more one way or the other for certain end game results. Still feel free to pick whatever dialog you want. It just helps if you go more fully one way over the other. If you're firmly in the middle without a majority one side or other, it will limit some choices in the end game. I think they tried to "reward" a player for being one way or the other but yeah. Sometimes an aggressive stance works better than a nice one! ME1 was the worst about this. It gets better in 2 and 3 though.

The gameplay in ME1 is a bit slower but the story is great so don't get upset if at first it seems a bit hard. They were going for a RPG with shooter elements. While ME2 and ME3 are a shooter with RPG elements.

I'll give some more tips when you get to ME2.

Mostly, enjoy this grand adventure :3