

Miranda for good Cerberus-specific dialogue. Bring Garrus for Tali's, best if with Area Overload. Bring Grunt for Mordin's mission and Mordin for Grunt's. Loyalty missions as they unlock: Jacob, Mordin, Grunt, Tali, Garrus, Thane.Remember to pick up a weapon specialization or the Widow rifle. Mordin and Miranda for a main story mission. I usually do Miranda's loyalty at this stage. One random mission so the game unlocks the next one.Nothing story- or gameplay-wise. Bring who you like. Miranda and Garrus for dual Overload against Geth shields. Bring Miranda when you can, but Liara is your best squadmate here with her Singularity.

This is often done later in the game, but: (1) if Liara was the ME1 love interest, Shep should go see her as soon as possible (2) even if not, the Shadow Broker ship becomes a hub and source of upgrades, as well as the ability to retrain squad powers. Important story-wise to have your leads, and Warp and Incendiary are useful against Scions and the Praetorian. Garrus and Miranda for dual Overload against many shields.
MASS EFFECT 2 ZAEED LOYALTY MISSION FULL
Mordin and Miranda for best powers Mordin and Zaeed for best story (but too bad that Zaeed only has one line in a mission full of Blue Suns mercs.) Plus a cool Prothean sphere in Shep's cabin.
