Hi Akhilesh,
You can mature DLP policy by
1)adding some new threat detection as per periodic security review and
2)adding exception to reduce false positive incidents.
Above both can be achieved for network and enpoints, for network u can prepare some list of senders which can be whitelisted and some can be blacklisted based on policy creation and classifiaction. At endpoints u can apply IP filtering solution to reduce false positive.Also u can detect or excluse certain file types,folders etc.U can designed effective and accurate detection keywords to detect more precise DLP incidents of policy vialtion.
reduction in false positive not only reduce application, server,network utilization but also aattention to in neccesay generated incidents which reduce time to handle incidnet.
Please also refer below links
https://www-secure.symantec.com/connect/articles/approach-fine-tune-dlp-policies