The key for me is deep conditioning weekly and sealing the ends after shampooing.
I deep condition at least once a week, and I make sure I drown my ends in conditioner before putting on a plastic cap. This has eliminated my breakage/split end problem for the last 3-4 inches of hair (which is where I had the most trouble).
Also, I've found that apply a tiny bit of leave-in condish followed by a small dollop of oil & serum mixed seals my ends very well. Not only does this keep frizz away, but it also keeps my ends from splitting. I like to use Redken's Moist Ends from their Clear Moisture line or Schwarzkopf's Bonacure Repair or Giovanni Direct as the leave-in for the ends. I like NTM Healing Shine Serum or Giovanni's Shine of the Times as the serum, and I like coconut oil or jojoba oil since they're light.
HTH
{DI}