In general you want a min of 8 gig ram, a discrete video card of at least moderate value of passmark score. Anything over 1000 may be waste of money. Best to have 2 discrete internal HD's.
Check if the screen has an IPS panel.
Even if you know it is IPS, it can still have limited gamut. Most backlights in notebooks have a 70-80% sRGB backlight, which gives a very flat image. A few years ago life was much easier: Dell and IBM still made 1400x1050 and 1600x1200 pixel sRGB CCFL backlit IPS monitor laptops then. Even a Retina MB is not as pretty as those were.
Apple's Retina MBPr at least has decent sRGB coverage.