Lots and lots and lots of practice helps.
As supplements: beta-alanine (I'm using Karno4 myself) helps.
As food source: try to push up your fat-oxidation by staying low carb on recovery days and the fuel your ride by carbs on cycling days. If the ride is very long, do a carb up the night before.

I'm seeing proponets of both a high carb/low-fat (15% fats is looooooooooooow!!!) and a low-carb/high fat diet. It all depends on
- what type of rides you do: slower endurance or faster performance rides (sounds like the latter but am not sure)
- if you're insulin resistant or not. From 2002-2003 I was on a near exclusively (cyclical) ketogenic diet and yet did just fine on longer rides of up to 375 mi/600K (brevets). At the time i was quite insulin resistant. Nowadays I'd not be able to go for longer than 1-2 hrs w/o carbs as carbs are now the preferred fuel.

With more carbs as fuel you automatically will get more lactic acid build-up. That's why it even pays for someone insulin sensitive to push up the lactic acid threshold by training it. Beta-alanine can help to clear it faster (or actually get it recycled faster). Especially useful when you're not able/willing to train for it as much.