How to Be Sure You and Your Squad Survive *SPOILERS*
*SPOILERS*
Your choices during the Final part of the game are largely irrelevant so long as who you choose for each role makes sense. For example when you need a powerful biotic don't use someone who is a split specialization. Otherwise make sure you buy the shields, armor, and weapon upgrades for the Normandy or you won't last long. Also make sure you complete all of your squads personal quests by talking to them, then completing the mission. This way they are more loyal to you and will be willing to work harder to complete the mission.
On one last note if you complete any side missions after "additional captives" are taken after you collect your squad you will not be in time to save all of them.


Faster Planet Mineral Scanning
For a faster way to scan the planets move cursor to the left or the right of the planet you're scanning and point both analog sticks the same direction. It will double the spin speed of the planet and allow finding resources on that grid line even faster.