By donating during a funding cycle — one vote per donor per cycle.
Votes should be earned by participation that costs something. Without a cost, voting opens the door to sock puppets, brigading, and participants with no real stake in outcomes. The mechanism the platform uses right now is a financial donation.
Each donor earns one vote per funding cycle by making a donation of at least the cycle's minimum. A larger donation in the same cycle does not purchase additional votes — the excess contributes to the matching pool, which is argued elsewhere. This keeps the voting roll a roughly even distribution of participants rather than a reflection of who has more money to spend.
Other forms of participation could also plausibly earn a vote — an officer of a group who has taken on real responsibility, someone whose sustained work has shaped the platform, other kinds of demonstrated commitment. Each of those should be argued out as its own case. For now, donations are the mechanism.
The minimum is ten dollars. Below that, processing fees and administrative overhead consume too much of the donation to leave meaningful funding. The ten-dollar figure will not be permanent — it has to move with inflation and shifts in processing costs over time.