It's a bit intimidating when you see the huge address space available, but in practice, it's not hard to deal with.
Let's say you are allocated a /48. That gives you 65K /64s to play with, each capable of holding rather a lot of addresses. Also the rounding error in 65K gives you a slack handful of other /<64 for other uses.
Personally speaking I call off /64 subnets from the /48 per VLAN. I set the router address as ::1 for each VLAN. I use ::xxxx for DNS (where xxxx is a repeated digit) and similar for a few other services. It's easier to remember.
Each box gets a SLAAC allocated address and all hosts are encouraged to also set a temporary address. This way we can find a system using the SLAAC address but the system retains a little privacy on the internet - or it would but we generally use a web proxy - ahh but that has a temporary address as well! Still, the ubiquity of IPv4 makes all this moot.
If you have multiple sites then break up the /48 into smaller bits but larger than /64 - enough to cover all eventualities. This will allow you to aggregate routing tables somewhat.
Frankly, assuming you DO have a /48 (I have one for my home, so I don't doubt it) then you should have enough space to cover most eventualities and schemes.
Now, if your setup is bigger - say multi-national and multi site then I suggest you investigate PI and then break that up by country/site/VLAN or country/locality/site/building/VLAN or whatever. You still get plenty of addresses in a /48 for all but the largest set up.