Mtm dress shirts and pants

[Biggs]

Hi, I'm getting a couple of MTM dress shirts and pants.  However, I don't have much of an idea on what to tell the tailor.  Can you give me some advise on what type of fabric to pick, what kind of cut/style(preferably something modern) and what level of stitching quality(e.g. 2-ply), to name a few?  Please elaborate on the details to eliminate possible bad judgements I could make.  I'm a bit scrawny, 5'10" and 150lbs.  Thanks.