Been a while, but at one time I was indoctrinated into the cult of triathlon, road and XC racing, and obtaining more speed is all those nutbars live for. I started out as a slug, but by the end I was actually consistently on the age group podium.
What I learned in the end is there's no shortcuts, putting in the training time is how you get fast. By all means make sure you're fueled up with enough carbs, have a banana and a coffee before heading out, get enough sleep, make sure you're well hydrated, your bike position is optimized for power delivery, you're running fast tires, not carrying excessive body fat, etc., but the overarching bottom line is you get out what you put in.
I was told by the fastest riders and coaches that hill repeats is the most effective way to fitness on the bike and the best use of your time.
Hills are upsetting, it hurts and you want to die. They're as much mental as physical Try sprinting the bottom, then sprint again as you crest to get used to an attack mentality. Eventually try and figure out the highest tempo you can hold throughout the entire hill without blowing up.
Ride hills more frequently. Everyday riding is a good goal, and then only miss the days when life gets in the way.
Maybe even get all crazy and write yourself up a training plan. Familiarize yourself with periodization- macrocycles, mesocycles and microcycles. Emphasis on the quality work phases i.e, tempo work, sprint work, hill work, etc. Plan out an endurance phase, strength phase and power phase. There's lots of online resources to help with this.