i usually copy SRO (and pretty much every other high-Elo gator for the past 3 years) by making sure to build Tiamat or a Timat item first.
The amount of lane pressure it gives is really instrumental - it's not just about the W cancellation.
i think that i tend to build slightly tankier than him AFTER the first item compared to high-Elo gators. i've always like to build Black Cleaver (even pre-rework) on him as a 4th item since it acts like a LW but with some health stats.
The following is in the context of older seasons, so the item paths are going to be different:
1st item was almost always Tiamat > Hydra.
2nd item was totally lane-dependent. Typically it would be Randuins or whatever item was stronger Banshee/Spirit Visage. If i was really ahead against an AP laner, i would go Hexdrinker since it gives you some defensive insurance but also let's you continue to pressure hard. i know Randuins is a bit weaker now, but Dead Man's plat works for the new season 
3rd item was generally "what the team needed". If someone was really fed, it'd be the defensive item to try to beat that (if i already went HP+Arm, i'd go Sunfire here). If our team was squishy, i'd build more defensive items (Locker, Randuins, Sunfire, whatever). i'd only build a damage item (generally TBC but sometimes Maw) 3rd if i was not only really ahead, but our team lacked damage (eg, something like Naut jungle, Braum support).
4th item was usually TBC as noted above. If i were really ahead and already had 2 damage items i'd build GA instead.
