There are pretty much two main problems that arise from people using CARP that cause failures. Those are using duplicate VHID's, and and use of the wrong subnet mask on a CARP.

The first seems simple enough. Use a different VHID on each CARP VIP you create. Unfortunately it isn't just that simple. CARP is a broadcast technology. Anything using CARP on that same network segment must use a different VHID. Worse, VRRP and HSRP (hot standby router protocol) use the same port number as CARP, making it difficult to troubleshoot on logs alone. My thought on this is to simply use a unique set of VHID's. If you are on a known safe private network, go ahead and number starting at 1. I have personally wound up on a public network where HSRP was conflicting.

The second sometimes needs to have the point beat home, which is to use the IP's REAL subnet mask. Don't use /32. Pretend you are using ifconfig to assign the IP address to an interface. You wouldn't use /32 there, so don't do it here.