For me, it is the gift cards! Give the cards to both people you know and those you don’t know. You can leave the gift cards at libraries, banks, post offices, etc. Don’t worry about losing them if not picked because you got the redemption codes with you at your affiliate center account and can give those lost card’s codes to other people.
Others can be words of mouth, organizing seminars, conference meetings, etc. Hope you get something from this. Thank you.