So You've Decided To Become A Bank Robber: Some General Tips For Success In Payday: The Heist
So, you've just installed Payday and you're not sure what you should be doing. Your question as it currently stands is too vague for a good answer, so instead here are some questions that you should be asking yourself.
1. Are you playing single or multiplayer?
If you're trying to learn the game by playing single player with bots, cut it out. The bots don't accomplish objectives on their own, so the only way you'll figure out how the game works is by trial and error. Don't do that. The game is multiplayer for a reason. Join a game of first world bank and play through it with real people. Don't worry about not knowing what to do; the other players can see that you're at low level by looking at your name (level is indicated above each player's head). You're not expected to know what to do at low level, someone will tell you if you mess up. Find a player who is higher level and make that person your wingman. Stick together, cover each other, and watch what he does. The things that he does are the things that you need to be doing in the next game.
2. Are you playing on easy?
It's called easy for a reason. Don't try to play a heist on a high difficulty until you know what you're doing. You'll spend all your time dead and no time actually learning.
3. Do you know the layout of the maps by heart?
The maps can be confusing, some more than others. Heat Street is the most straightforward, Diamond Heist and Mercy Hospital (Plan A) are the most difficult. Spend some time running around the maps learning where everything is (between assaults is a good time for this). You should be able to look at the location callout near the character list in the corner and immediately know where each player is. When you get better, you should also know what stage of the heist you're in and what each player should be doing in that part of the map.
4. Are you listening to Bain?
Bain is in charge for a reason - he knows what's going on. Listen for his voice on the radio and watch for the objectives in the corner of the screen. If you've forgotten what you're doing, or what you need to be doing next, he can act as a reminder. Also notice when he says assault wave coming in 30/20/10 seconds, and take cover!