I had a sim partner when I went through that wasn't very helpful. It really made things hard. I will say what others have said, get a good partner who you get along with and will help you.

Also, know flows and memory items cold. I practiced them while having the TV and the radio on in the background. Try to get distracted as you can and know them well enough to be able to get through them easily.

Practice flying approaches on flight sim with the fastest plane you can find. The flying isn't realistic, but teaching your brain to do IFR quickly will help. Have someone give you holds, change runways, and other stuff to keep you thinking so aren't prepaired and so that you get supprised.