Pnl difference Real Trade vs Paper trade

Same strategy when executed in paper and real there is huge pnl difference, how to avoid this difference, how to get pnl in paper trade to get same pnl in real trade.

Use
Live Off-Line

I am using strategy PNL >= 4000 with Using Live Off-Line but Live Auto PNL = -2000 ( I can understand slippage) but this much slippage then there is no need of Live Off-Line testing a Strategy.