This is a game where both the characters and the players need to be a cohesive, functioning team, and so it's not unfair to ask that you make some small sacrifices in motivation or build to account for that, which point is elaborated upon below. Among the main things to consider, however, are the following:

  1. This is a game about a city. The whole game takes place within the city of Waterdeep. You will rarely, if ever, leave it, and then only briefly.

  2. Your characters should be invested in the city and its wellbeing. This does not need to be for altruistic reasons, but it needs to be a part of your character. You need to care about the city; you should have loyalty to it, feelings for it, a history with it. It should be easy for me to motivate your PCs to act in the interests of Waterdeep.

  3. Your characters need to be well-acquainted with and loyal to one another. Despite your differences in motivation, goals, skills, lifestyle, etc., you should be at least as invested in your fellow PCs as in the city. You need reasons to work with them, to stay with them, to go to them before you go to other people.

    Your character can be different, but they should not suffer from an insanity or other condition that prevents them from empathizing or forming emotional attachments. The party must function: No backstabbing, no plotting against one another, minimal friction, etc. Since realistic characters are demanded in exchange for a realistic setting, this means people should to be free to pursue their characters rather than restricting certain behaviors (like seeking to punish fellow PCs who seem to deserve it). To that end, you should strive, at the beginning, to develop and acquaint one another with characters that have reasons to mesh well, instead of leaving holes where animosity could later develop through a lack of understanding or an incompatible difference in some other traits.

  4. This game is not kind. You should make known in advance any topics that make you uncomfortable or trigger you, so that you aren't surprised later on, when something like gore, sex, crime, etc., is addressed. This is a gritty, noir-type game with a lot of horror elements; there will be things like success and friendship to cheer the mood, here and there, but it is overall a dark game. You need to clearly understand that and explore preemptively one anothers' limits to ensure hidden lines are not crossed by accident.

  5. There are spoilers everywhere. Don't go looking for Waterdeep material or answers to questions you think your character should know; always ask the GM. If it isn't supplied from the beginning, that's what skill checks are for. Tidbits may also occasionally be handed to you without a skill check, as new subjects come up, because your character might reasonably know something (but it might not have been thought of, until then). If you go Googling, though, you're bound to find something that will spoil parts of the setting for you, since it's very easy to do (Waterdeep being a favorite FR location, and the information being pretty freely available). Not to mention, everyone hates people who assume.

  6. This game is about teamwork. If you cannot work together, you will fail, and your PCs will probably die. Exceptional teamwork will be rewarded, but no fudging will be done to protect shoddy teamwork. It is your responsibility to stay in touch with one another, as well as to familiarize yourself with any assets or allies you acquire IC, and to plan carefully. It is not considered metagaming to consult with one another and talk about your plans for an upcoming level, or a certain feat you're taking and why, etc., since you'll still be expected to RP new developments in your character, anyway. Whatever helps you work best together, you should do. Toys will be provided during the course of the game to help facilitate better teamwork, and to avoid problems like "you didn't have enough time to talk about that" and "that plan's not believable, you couldn't have had that conversation," etc.

  7. You will be required to develop your character and demonstrate growth. Even if all of you can be counted on to display dynamic characters and evolution, it must be explicit so specificity is not replaced with assumption. Static characters are boring. Don't play them. Don't plan for them. Plan to react and grow. Start thinking now about changes you want to achieve later on, and work with the GM and one another to understand and reach those goals.

  8. You will be required to interact with others. There should be no standoffish or lone wolf characters. You will have NPC allies, as well as contacts and more, that you should plan to build relationships with. These will not be cardboard-cutout characters; they are as real as your own characters, with agendas and emotions and flaws that are just as compelling (if not more so, because theirs will often be secret, at first). You should treat them like fellow PCs, not like inanimate objects that can be manipulated with a Diplomacy check.

    If it helps, think of them like Bioware (Dragon Age/Mass Effect) party members. They have depth, they have pasts, they hurt, they love. You won't be disappointed, but you have to invest. Don't make a character that won't be interested in connecting with others.

  9. This game is complex. The campaign runs the gamut from sewer crawling to high society parties to boring government functions to surreptitious combat in alleyways. Think about how your character not only fits into the city, but will function within it. Be prepared to change your tactics and try not to lock yourself too tightly into a single, specific role that will later be difficult to break away from. Consider adding new skills and feats you hadn't thought of as your character develops, in response to experiences. Have a plan, but leave yourself wriggle room.

  10. You are small fish in a big pond. No matter how much you may disagree with the design choices, it can't be helped that Waterdeep constitutes a generally high-level region in the setting. Simply because of the way the d20 system is made, it necessitates that most of the people you encounter who matter, at all, will average 6th or 7th level and up, or thereabouts. Regardless of your PCs' opinions of themselves, you, as players, need to be aware that Waterdeep is still dangerous, even at 5th (or 6th) level, populated by master thieves, epic-level archmagi, consummate warriors, and more. Town guardsmen here are not pushovers. You are not invincible. You need to know that—while the rank-and-file commoners off the street don't fall into this category—there are still scores, if not hundreds, of folks in Waterdeep who can cut you down without any effort.

    This isn't to make you feel insignificant. It's to ensure that you know where you stand, so you aren't frustrated when NPCs resist your spells, make their saves, dodge your well-aimed attacks, or pull out maneuvers and tactics that generally surpass your level or expectations. Nothing will be done with any NPC that you could not potentially do with a PC—they're using the same rules you are, after all—and many of these NPCs are canon. You're just starting out small. You'll grow.

See also:
Campaign Traits