Since there's a lot of new players on (including me), a good way to rank the players could be a ELO like system, the one they use to rank chess players of all world.
I did something like that for our dart team, now that we're locked in the house and it's working pretty well.
What you need is a starting point and some data you think it's the most useful to evaluate the player. Just a few would suffice, for example, overall average (most important one), form average, #legs for 180s. With those data, you can elaborate a value. Take my numbers: Overall avg 56.29 (value 20), Form avg 58.54 (value 10), #legs for 180 28.15 (value 2). So 56.29*20+58.54*10+28.15*2 equals 1767,5 cut 1767.
This is my ranking value. Using ELO like, if i play opponents with 1825,1700,1850,1889 and my results are W,L,W,Tie, my new value will be 1798 assuming a 'k factor' of 40 (it can be different). (Source Wikipedia ELO ranking system)
When a new player arrives, he will get an initial value based on the overall average of the players already in, minus a 20/30%.
At the end of the day, every player who had at least 3 games, will have his new value elaborated.
It's a ranking that can run all year, and it's been quite a success with my club. 
It looks more complicate than it is, as I run it with just a excel sheet (actually 2 pages) =D
If (or when) you want to take a look at it, I can send it to you, of course.
Sorry for the long post... 
Fabio

I like the Elo system.  Used not only in chess but also in sanctioned Scrabble play.  The average per round is a general idea, but doesn't encompass all aspects of the game like a result system like Elo can.