Best way to play through Mass Effect 2
As soon as you can get Mordin start using him and Miranda. They don't have the best weapons but they have great powers. If possible use Tali's power ability, energy drain, which acts like overload but also restores your shields. Use the soldier class and put skill points into squad disruptor and squad incenerate ammo powers, adrenaline burst, and energy drain. While using Miranda put points towards warp and overload, and put Mordins powers on incinerate and cryo blast. With the exception of ammo powers and cryo blast, put all points towards attacking only one enemy at a time. For cryo blast can work good as a crowd control for enemies with no shield or armor. Between Miranda's overload and your soldiers energy drain and disrupter ammo, most machines fall quickly. This also destroys most shields very quickly. Using Mordin's incinerate and Miranda's warp, as well as your incendiary ammo, you can take down armor pretty quickly. Warp is also effective against biotic barriers. As the soldier has adrenaline burst they can put alot of rounds into the enemy without being hit. Once the actual health is showing Mordin's incenerate works great for quick kills while his cryo blast can freeze groups giving you more time to react. Miranda's warp is also effective agaisnt health and as a soldier once the health is showing a few well placed rounds from an assault rifle will kill most enemies.