We (SingletrAction) have built 2 and are working on a third with a planned rebuild of Stainburn and an extension nearly complete at Buck Woods.
McCormack's book is excellent.
Plan and scratch out the shape
Drainage.
Build up from ground level (out of standing water).
Build the berms first, then fit the rollers.
Don't put the rollers too close together (peaks at least a bike length and a half apart).
Drainage.
Build it with mineral soil, either the local ground or import (some Quarries do reclaimed soil which can be cheap, c £6/tonne).
Get some decent tools (long handle shovels, rakes, tamper, barrow etc)
Drainage
Dig efficiently
Water it in and pack it down
Wait
Ride
Refine
Loose dirt packs down by 25 to more like 50%. Build as big a pile as you can.
Drainage
Not knockingthe DJ folsk and it depends what sort of PT you want but think smooth and flowing and don't go too huge. Rollers don't want to be big and peaky. A straight of 3 or so well shaped, 300 to 450mm high can build massive speed.
IMO you don't need a roll in. If you've got one then great but if you have to build it then it's a lot of effort for something not essential.