[Calvin]

Varyon has already mentioned Energy Reserve, which is very nice, but the other two sources I suggest seeking out are Powerstones and Inanimate Sacrifice from Thaumatology 55.

Powerstones are like rechargeable batteries, and I have two main strategies for their use:

First is to buy the largest two I can afford and hide one in my shoe and the second somewhere on my head. (They need to be six feet apart to passively charge properly.)

Second is to buy tons of powerstones with signature gear and use Charge Powerstone with No Nuisance rolls to keep them topped up.

Inanimate Sacrifice is a different way to get energy out of objects. Divide campaign starting wealth by 250, and that's how much value of goods you need to sacrifice to get 1 FP. Your GM might set certain rules around how that might be done, so I recommend reading about it in Thaumatology 55.