A rune page for Aphelios reasoned from its class, range and damage type — with the thinking shown rather than a win-rate table.
Rune pages get copied far more often than they get understood, which is why they stop working the moment the matchup changes. Aphelios is a marksman whose job is to deal damage every second of a fight from behind people who can absorb one.
550 attack range means Aphelios wins by not being where the fight is. Spacing is the whole skill, not a detail of it.

Precision — Marksmen win by attacking for the whole fight rather than winning one exchange, so the keystone that rewards sustained attack speed fits the job description.
Attacking an enemy champion grants you Attack Speed, up to 6 stacks. At max stacks, deal bonus adaptive damage On-Attack.
Killing a target heals you.
Takedowns on enemies grant permanent Attack Speed.
Deal more damage to low health enemy champions.
A starting point reasoned from class and range, not a win-rate ranking. Matchups change it.
Take Moonlight Vigil at levels 6, 11 and 16 — the ultimate is always worth the point it costs.
None of the basic abilities changes cooldown as it ranks, so the max order comes down to damage scaling and the matchup rather than uptime.
This is reasoning from the cooldown data, not a win-rate ranking — a matchup that punishes you can invert it.
The page above assumes an even matchup. Against a lane that beats you up early, survivability runes buy you the levels you need; against one you outrange, damage runes compound the advantage.
Aphelios is mana-gated, which is the real limit on how often you can contest a wave early.
These are the designers' words, not ours — the tips shipped in the client for Aphelios.