>>1924808First I clean thoroughly with saddle soap and a horse hair brush. I use Fiebings yellow.
Condition with some neatsfoot oil if needed but if they're new it should be fine.
Let the boot dry for a day or so.
Then heat the shoe slightly with a hairdryer or something (not too hot) and apply a generous amount of sno-seal or straight bees wax if you'd like.
Use a soft cloth to work the wax into the shoe. Work it in, re-heat, re-apply, repeat until the boot stops absorbing it. Really work the leather with the cloth to build friction.
I picked up leathercraft a couple years ago and I've been doing this to all my homemade outdoor gear as well; minimum every year, more often with harder use. Sno-seal seems to be the best as long as you don't mind that it kinda smells slightly chemically, but for boots it doesn't matter.
As long as you take care of leather, it'll last a long time.
Also keep in mind it will darken the leather, if you care about that.