I would say read every book you can find on multi engine, single pilot IFR flying. I would start with the jepp manaul, and read the terminal section and
how it applies to you as a pilot. Eg when can I descend below LSALT?, how much obstacle clearance is provided in a missed approach, or at the 25nm MSA etc. Break it down into something
you can understand so you know what you can and cant do. Wait till your flying a baron/c310 etc into an ALA at night, you want to be sure when you can go below LSALT, MDA etc.
Besides the jeppos, I recommend "Weather Flying" by Robert N Buck, and "Multi Engine Flight Manual For Professional Pilots" by John Chesterfield and Peter Hay. These two books to name a few helped me alot.
Start simple. IFR training is meant to build on your VFR training. Its still heading and time. Its still straight and level, or a descending turn etc, just that the descending turn might have a limitation on it which says you cant go any lower until your established.
Enjoy
