How to tune the SQL

Experts,      Can give me some idea for the SQL?  SQL detail as following:
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SELECT /*+ parallel(statclaim) parallel(lastendorse)*/
    LastEndorse.statdate,
    LastEndorse.StartDate, LastEndorse.COMCODE, LastEndorse.RISKCODE, LastEndorse.SHAREHOLDERFLAG, LastEndorse.BUSINESSNATURE,
    LastEndorse.PolicyType, LastEndorse.CENTERCODE, LastEndorse.Agentcode, LastEndorse.Handler1code, LastEndorse.AimClient,
    LastEndorse.UnderwriteCode, LastEndorse.SumQuantity, LastEndorse.GroupCode, COUNT(*) as NoPaidCount, 0 as SumClaim, 0 as CarClaim,
    0 as PersonClaim, 0 as SumLoss, 0 as CarLoss, 0 as PersonLoss, LastEndorse.ANADate, LastEndorse.CountryNature,
    LastEndorse.ChsABKindFlag, LastEndorse.ChsMKindFlag, LastEndorse.RelatDim, LastEndorse.BusinessKind, LastEndorse.BusinessClass,
    LastEndorse.UseYears, LastEndorse.InsuredType, LastEndorse.SeatCount, LastEndorse.TonCount, LastEndorse.UseNatureCode,
    LastEndorse.CarKindCode, LastEndorse.businessflag, StatLclaim.reportdate, StatLclaim.damagestartdate, LastEndorse.underwriteenddate,
    LastEndorse.ExhaustScale, decode(StatLclaim.catastrophecode1, '007', '1', '0'), LastEndorse.businesssource,