NIMH don't have the memory problems that the packs from long ago had so there is very little you have to do.....but this is what i do.

If your charger has a discharge-charge cycle I do 5 cycles just all at about 1 amp per 1000 mah of battery (i.e. 2000 mah battery would be charged/discharged at about 2 amps). That gives me a baseline capacity of the packs if all the cycles come in close to each other.

For NIMH packs I keep them charged at all times and usually don't run them to close to dead. Not like the old days when you wanted to drain them before recharging to prevent memory issues. Otherwise i store indoors in the summer to keep them out of the heat.