I'm sorry for not posting for a while there was a problem with the web site.
Check brood chambers.If all the brood is in the upper part of the brood chamber, reverse the upper and lower brood boxes. Reversing these will cause the queen to use both boxes to lay eggs. In about two weeks reverse the boxes again.
Feed overwintered colonies one-to-one sugar syurp to stimulate brood rearing.
Check the brood chamber for disease each time you open the colony.
Prepare honey supers with new foundation. The major honey flow is not far off.
Check for queen cells. Swarm season is just around the corner. This is a good time to split your bees if you want to increase your numbers or to prevent your bees from swarming.