Ok have 2 different questions here.

First when I try to use the key in my 98 F150 to unlock the doors, I have to wriggle it around quite a few times before it finally unlocks. Sometimes I just give up and use the keyless entry. Any ideas what the problem could be?

Second is my tailgate handle. Sometimes it opens just fine. Other times i'll pull up on the handle, it moves upwards just fine but it doesnt unlatch. Any ideas on this?

 

The door lock problem might be resolved by lubricating the lock cylinder. It sounds like you don't use it much and they tend to stick when not used. Try spraying a lubricate into the hole for the key and let it sit a few minutes and then try the key. If that doesn't work, then the latch might be the problem. Again spray lube into the latch where the striker hits it. Open and close the door a few times.
The tailgate could be the same problem, where you would lube the end latches on it, or remove the cover on the inside of the tailgate. Then you can see what is going on with the latch. Sometimes the handle assembly just needs to be replaced. It is held in by two bolts and the plastic clips just slip off with a little help.

 

I tried WD-40 on the door lock to no prevail. Should I maybe try that graphite spray stuff or do you think i should just replace it?

 

If WD-40 didn't fix it, then you will have to remove the door panel to see if the problem is with the lock cylinder or with the latch assembly. You will have to disconnect the rod at the lock cylinder to see if that changes the way it turns or doesn't turn.