When in doubt, Massage the Fundus! LOL. Obviously only after the baby is out. If mom is bleeding too much, that is usually what they are looking for in terms of the first nursing intervention.
When the baby is still cooking, always think oxygenation and perfusion. What interventions will promote those?
Know your role adjustment stuff- transition to parenthood, family bonding, etc.
Know the different prenatal tests and when they are indicated, risks of each, etc.
Rhogam, Vit K, erythromycin, APGAR, the basics of the neonatal resuscitation algorithm
Nursing role in birth emergencies- shoulder dystocia for example
Do you have access to HESI practice tests? I find those really helpful.