First indications are your schedule slipping & your cost going into overrun. Earned Vaue Management data is useful to track these figures. Here Cost Variance & Schedule Variance on the date of assessment will indicate cost and/ or schedule slippage. Estimate to complete, ETC & Estimate at completion, EAC are also good data for assessment  

Cost variance can be due to Scope creep, or escalation in material cost from estimate. Check assumptions of output for labour material plant & revise assumptions n estimate . Redo project estimate. Redo the WBS & get buy in from stakeholders.

 For Schedule delay look at doing more parallel activities  

Persistent delay could be due to poor risks management. Rework the risks analysis with a more elaborate effort to not miss all the possible risks. Keep tracking old & adding new risks at regular intervals, maybe once a month.      Looking for better project delivery? Open https://pmw.net.co/online-webinar/?nm=confirmed&nk=121-fca1056b6b ,   and also watch a video on a project issue too!