*disclaimer* - this is just my experience.
I would still start with the simple stuff - it's the most common - 97% of the time it will be this stuff
in order:
1. Ignition - plugs, wires, coil output, primary ignition stuff like the pickup coil or + coil voltage low.
2. Fuel - pressure, volume
then *after* you verify
- as in measure/check etc., not just say "well it's new so it must be good" -
all this stuff, start looking for what I would call "uncommon" stuff which makes up the other 3%
I've had a fuel pump eccentric tab shear off and leave me on the side of the road with no fuel pressure, but I would never suggest that someone pull their timing cover off to check that just because their car runs bad.