what parts are needed for a good tuneup?

My 2000 3.3 is in need of a tuneup. It misfires frequently, slight un-smooth idle etc, but I am still getting good mileage, about 20,5 mpg
It also pings at higher RPM, I did 2 seafoam tratments, but it didn't help
My questions: which parts should I replace?
Spark plugs (looks to be a pain)
Spark Plug wires
Fuelfilter (where is it located?)
any other parts?
thanks for the advice

Spark plugs - you can get at the rear set either from above or below. I personnaly get them from below. Well except for the passenger side rear plug. Just rotate the alternator forward. If you go at it from above you either have to remove the windshield wiper tray or the intake plenum or both. Make sure you buy a name brand platinum plugs.

Plug wires - I would go with OEM wires from the dealer. Aftermarket wires are a hit and miss proposition. Not that I recommend it but I am pushing 210K miles on my van with the original plug wires.

PVC valve

Fuel filter - I suppose if the van has over 100K miles on it you could consider changing it. They are meant to last the life of the van. It's located on the rear top of the tank. I still have the original filter on my van. Some insist on changing it. Maybe the same folks who insist on installing Zerk fittings on suspension parts.

Accessory drive or surpentine belt

Might consider changing the brake and power steering fluids. How's the tranny fluid and filter?

www.edmunds.com lists the scheduled maintenance for most vehicles based on the miles you have. Might check it out.