Very important question before providing clearances to pour concrete. I would follow following steps.

1. Ensure Contractor has bar bending schedule and approved drawing.
2. Ensure reinforcement used are approved grade and test certificates are in place.
3. Check  diameter of rebar ( reinforcement)
4. Check spacing
5. Check banding radius
6. Check number of bars
7. Check laps are of proper length. Some time couplers are used to join the reinforcement. Couplers must be approved.
8. Check proper cover to rebar is in place.
9. Covers should be approved
10. Check the reinforcement installed does not sag  or move. For this ensure you use chairs.
11. Tie the rebars together using soft annealed lining wire and turn the know inside.
12. Reinforcement must be clean without any dirt or coating.
13. Some time special reinforcement steel is provided around openings. Ensure this is in place.
14. It is normal for QC departments to use check lists for this.

Hope this helps.