In reply to elliot.baker:
Fairly new MTB rider here. Just a few things that I haven't seen mentioned, that I've picked up on the way (you may already know them).
Firstly, if this your first ride, you've chosen a very tough one in terms of grades: it is rated red/black. Also I believe it's in the 'Epic' section of the book. So, wow! Hats off to you. That's like doing HVS on a first climb.
I would recommend getting the book Peak District Mountain Biking (and/or White Peak) and working through the first section, reds/blues. I recommend the Ladybower Lite (also on Viewranger).
Also, are you already familiar with trails such as Gisburn Forest? I have found them best for skills and conditioning, being more varied with climbs and DHs than cross-country. Jump on the reds, it's a LOT of fun if you haven't yet.
Lastly, the main skills I've used are: putting ass over the back cogs when going down hill (lowered seat). Dropping/raising the seat prior to taking an uphill/DH. Locking elbows to make a square to put weight over bars when going uphill (raised seat). And 'pumping', pushing down on forks on the up/down of ramps for free speed. I'm starting to get more confidence with getting air on jumps so something is working. I use a hardtail.
As for conditioning, just do more MTBing. I trouser cycle to work, which helps. And a local skills park next to Manchester Cycling Centre.
Good luck! PM me if you ever want a riding partner.