Does anyone have a recommendation for a build or playstyle? I actually did hop on the game and play it briefly a long time ago, but I never got too far - I used a stealth build with the bow, did okay, but I would like some tips for later, if possible.
Depends on whether you're playing on PC or console. From what I've seen, console players are much more likely to consistently engage in melee combat where many PC players fall more along the lines of "I'm carrying a melee weapon for the sake of having one". Along the same lines, PC players are much more likely to carry high-damage long range precision weapons whereas console players tend to favor shorter ranged shotguns and other rapid-fire weapons.
It also depends on what the mission is. If it's something like a spy mission, I'll probably just pick my Loki and be invisible forever because the goal is to crack the vaults, not murder everyone and being invisible just lets me rush through the mission without alarms going off or people clustering in the doors I need to go through. If I need to dish out the murder, here comes Saryn or Mesa ability spam for AoE/line of sight death.
Sure, nothing is really stopping me from taking my Loki to another mission type, staying invisible forever and dishing out the damage but I don't really feel it's as fun or effective as breaking out Mesa/Saryn/Titania. But until you get to the late game, pretty much everything is viable and by the time you get there you'll know enough to have a good mix of survival and damage.
TL;DR - If a weapon has a high crit chance, make that chance higher and give it crit damage.
Multishot is always good (more bullet for your bullet).
Stealth is always optional.
Mobility is your friend.
Warframe abilities are there to be used, and not all abilities are equal.
Anything big and/or glowing in a color should be killed first.
If you need more firepower, recruiting/LFG chat will almost always provide it.