In the competition day
Warm up: The aim is to elevate muscle and body's temperature at an optimal level. An increase in warm up intensity in the cold days and a reduction in the post-warm up recovery has been shown to improve performance. When time between warm-up and actual start of competition is long, use strategies like passive heat to maintain muscle and body temperature.
Postactivation potentiation: It can be induced with exercise intensities ranging from 75-95% of 1RM. The optimal recovery period is 8-12min. Research also suggest the use of plyometrics.
Hormonal optimization: This can be achieved by various means such as:
-High-intensity training 3-7 hours before competition
-strength training 3-7 hours before competition (see postactivation potentiation above)
-ischemic training via partial working muscles blood flow restriction.
It must be noted that evidence is very limited so far. Also the existing research is mainly in healthy individuals and not in competitive and, more importantly, high level athletes.
For further reading
Kilduff et al (2013). Int J Sports Physiol Perform