Now’s the time to build any relationships you’ve been working towards (as long as you’ve been speaking to your crew between every mission). By now you should have invites for visits to your cabin from multiple sources (Traynor, Allers etc).
It’s also a great time to scour the galaxy some more for items to give to people on the Citadel, helping to complete more of the side-missions before they effectively ‘time-out’. If you’ve got Garrus in your game, then chat to him near the docking bay for a cool opportunity to have an interesting conversation with him. Also, if you’ve got the ‘From Ashes’ DLC, then your Prothean buddy can be spoken to in the Citadel on the Embassies level.
As per usual, talk to all your colleagues for extra reputation points, making it easier to gain additional conversation options for later in the game. If she didn’t die in an imported Mass Effect 2 save, you can continue your conversation with Miranda via the Spectre messaging terminal.