From the many job postings that I have been looking at it seems that employers would like an applicant to be proficient in VLookup functions, formulas, macros and pivot tables and pivot charts. It seems like that this is not a big task to master these things, but there have been whole books about 300 pages long written about pivot tables that you might find interesting to know.
As for macros and VBA, it is always going to be rather the challenging. Having dappled with the issue myself, I think the best advice is to look to reference the code you need to build the different models in Excel or the different tasks that you might need to do and keep looking back at this reference. Trying to memorize or otherwise learning the macros and VBA is really futile. We all have better things to do!!
Again, it's like what I have said meeting someone you know and like and who likes you also will go a long way in helping you and your investment banking career compared to mastering a technical skill.
