I find that Pantheon is most effective early game, so i find staying in top lane farming like most solo tops do would be wasting his potential. Therefore my build consists of two things:
1. Getting atleast 2 (preferably 3) gold per 10 items
2. Then roam the map and gank, with and without your jungler.
Gold per 10 items actually generate a lot of gold. And pantheons ganks are, in my opinion, quite strong and there is a quite large chance that these ganks will bear fruit and therefore provife the gold needed to snowball. If in the unlikely event that kills are not found, your gold per 10 should sustain you enough and you can always return to your lane for consistent gold.
basically my build goes like this:
1.Start with boots and 3 pots
2. Farm enough for Heart of gold and philo stone. Add avarice blade into the mix if you have a surplus of gold. At this point you should commence roaming
3. if your roaming has been successful rush a bloodthirster and get brutalizer. If not go a more defensive aproach by commencing to building a warmogs.
During late game you can sell or upgrade your gold per 10 items as you wish to make room for those major lategame items that are situational and depend on the team.