Firstly, credit where credit is due.
https://www.playstationtrophies.org/forum/topic/182334-hardc...Mass Effect 11. Make a save after you reach Saren the first time in the Citidel, before you go down to the final fight.
2. Complete the game.
3. Reload the save you made in step 1.
4. Change the difficulty to Insanity and save over your save from step 1. (remember to SAVE your settings before you exit the settings screen)
5. Start a new career and import your character that you just beat the game with.
6. Change the difficulty to Insanity while on the Normandy. (remember to save your settings before you exit the settings screen)
7. When you are on Eden Prime make another separate save.
8. Reload your previous save from step 4 and beat the game.
Explanation: The reason that this method works in Mass Effect 1 is because, unlike in Mass Effect 2 and 3, Mass Effect 1 counts your NG+ career as the same career from your first playthrough. Because of this, when you load your first save that you made (the one just before Saren on insanity), the game thinks that you haven't changed the difficulty from when you set foot on Eden Prime.
Mass Effect 2 & 3Unfortunately, no such cheese exists for Mass Effect 2 and 3. My recommendation is that you import the file of a previous playthrough. I also recommend that you use a class that you are most comfortable with. If you are still struggling there are many guides that exists from people that wish to min/max their characters.