Register your assigned IP range in the RIR, with up-to-date contact information, including abuse contact information. And regularly review if the information is still up to date.
As described in [ITHI] ICANN is working on an initiative to improve the quality of (amongst other) IP address registration, by measuring the quality.
As information is relevant it is a good idea to register your network in the [PeeringDB], as it facilitates the exchange of information related to Peering. It is a database of networks that are peering, where they are peering, and if they are likely to peer.
It is a very good idea to register you routing policy at [RADB] or your local RIR. There are some authorisation checks possible when describing your routing policy in your local RIR [RipeDbIRR]. Some connectivity providers (peering or transit) require you to do so. Next to publishing your own routing intentions, it supports the construction and maintaining of routing filters and router configurations and it assures diagnostic and information service for network management. Routing policies are described by using the Routing Policy Specification Language (RPSL) conventions. A good tutorial on using RPSL can be found in [RFC2650].