How to improve this sql query?

I have a user asking me to improve following query. I am not sure where to start. By looking at the query, it seems try by the subquery to find the top 10 eventid , then pull other information from the main query. 
Our DB version is 11.2.0.3.

Please kindly help me here.

Thanks.

SELECT inet_ntoa(s.SRC_IP_NO) AS sourceIpStr, LPAD(s.AGG_GROUP_TS, 9) AS aggGroupDate, SUM(s.EVENT_COUNT) AS eventCount

FROM SRC_IP_HGRAM s

WHERE s.AGG_GROUP_TS >= fromDate

                AND s.AGG_GROUP_TS < toDate

                AND s.LOCATION_ID = locationId

                AND s.CLIENT_ID = clientId