since you have a 98, you have a spark plug cover you will have to remove to get to the spark plugs. as you have noticed from your new wires, the spark plugs are pretty far down in the head, so you will need a decent length extension to get to them to remove them.
the fuel filter is on the drivers side of the fire wall, and it's fun to replace. you have to loosen the clamp holding it on and remove the clips holding the fuel lines to the filter. before you do that, bleed the system so fuel doesn't spray out everywhere. bleed the system = remove fuel pump fuse and run car till it shuts off.
air filter is fairly easy, just release the clamp that holds it on, pull it apart enough to get the filter out and put the new one in.