RicOlie_2 said:

Perhaps Obi-Wan's ghost could be really wordy? He could explain what the force is every time he tells Luke to use it, which should be far more frequently than he does now.

But when he appears on Hoth, he simply says "Run, Luke, run!" and disappears.

Obi Wan should say "run, Luke, run!" every single time Luke runs in all the films:

• Luke fleeing the cave

• Luke running to his speeder for the AT-AT battle

• Luke chasing the AT-AT to toss the grenade in it

• Luke running to check on R2 after he gets spit out by the swamp monster

• Luke running through the swamp with Yoda on his back... with a possibility of having Yoda annoyed by Obi Wan and saying something back

• Luke running while sneaking around Cloud City, just before Boba Fett shoots at him

• When Vader makes Luke drop his lightsaber Obi Wan could yell it out, and again after Vader tosses debris at him

• Obi Wan could try telling Luke to run after Vader says "Obi Wan never told you what happened to your father..." so that it seems like Obi Wan is trying to hurry Luke to jumping. Then when Luke asks why didn't he tell him, Obi Wan could say something like "Obi Wan don't seem to remember your father. Stay here. Luke's destiny lies on a different path from Obi Wan's."

Of course, these examples are just for ESB. The "run, Luke, run" could be an ongoing gag.