How do other clubs sell matchday tickets that sell out all the time ?
I have experience of Bournemouth (AKA 'AFC Drawmouth') system:
There are 3 points categories per supporter (Home, Away, Cup). You gain one point in the relevant category each time you attend a match. Points carry over to the next season, but only for one season (so the maximum home or away points someone can have is 38 - i.e. 2 x 19 matches).
Tickets go on sale in stages, with 'maximum' points holders first, with further drops every couple of days to lower points holders.
You can only buy a ticket yourself, or for someone else, if you/they have the correct number of points.
In reality this means that 'loyalty' is rewarded (which is good), but as home tickets never really drop below about 10 point mark, this means that a whole generation of kids have not been able to get a home league ticket at all (for past 10 years or so) - which is obviously bad.
Capacity is just over 11,000 - with 1300 for away supporters, and approx 7,000 season tickets. So mad scramble for remaining 3000 tickets.
Currently there is no paid membership scheme.
EDIT: Season ticket holders have no 'advantage' with away tickets. The system works in the same way as for home tickets, with the 'maximum' away points at any time being 38 (reset to 19 at the start of the following season). Much easier to get an away ticket than a home ticket, and indeed many fans are effectively 'away only'.