My dad has a 6'6 fiberglass falcon spinning rod with a quantum energy spinning reel. It is from the early 2000's but that is beside the point. Any way he used to use it rarely when fishing for stripers on fishing trips. But now he really doesn't go on any big trips, unless it is with me to the local river, or his friends pond. he lets me use the rod, but I have no idea what to use it for, i used to throw cranks on it a few years ago before i could use a BC rig, now all I use is a BC, but I would like to use this rod and reel. since it is a fiberglass spinning rod I have no idea what lures are best to use with it.

Crank baits.

Yeah I can't think of anything else either, but i fish crankbaits on my baitcasters.

Well you asked for the best use for it and it definately is cranking. Just rig it up with a crank bait and you won't have to change lures so much.

The fiberglass crank bait spinning rod I used to have was rigged with 20# braid and I used it for deep cranks.

Use it with lil 1/8-3/16 treble hook lures. 3/16 Rapala Shallow Shad Raps are one of my go to baits when bass are finicky.