This is a very common question:
When gluing on the cork handle, do you put glue on the rod blank, inside the cork handle, or both? If I put glue inside the handle, I get glue on the upper part of the blank as I slide the handle down the blank. 
Also, it is hard to get glue inside the entire handle length. If I put glue on the blank, the glue pushes down the blank as I slide
the handle on. If I am using a handle with an insert, the excess glue ends up in the insert recess and is hard to clean out without getting glue on the exterior of the handle. What do you use to clean up excess glue from the blank and cork handle?

I put the glue on the blank only and I put the glue about 2-3 inches above where the grip will be mounted. Any 2 part epoxy adhesive will work to glue on a preformed grip; some rod builders prefer a fast set glue over a slow setting glue. Either works just fine.

Use a tapered reamer to make sure your grip is not too tight, nor too loose; just right. Make sure that if you use a reamer that is a glued-on grit reamer that you blow air to remove all the bits of grit that came off during the reaming process. Dry fit your grip after blowing the tapered hole and make any adjustments before mixing your glue. As you rotate and twist your grip onto the blank the glue will coat the inside of the grip, I rotate the grip on the blank approximately 30-40 times before stopping at my reel seat mark. If your grip is too tight before gluing you will simply push all the glue out the back end of the grip and into the hood or onto the reel seat.

Applying glue above the front of the grip

Rotating grip so glue is even

Make sure grip is all the way to your stop mark/tape

A little bit of glue clean up may be required at the bottom of your grip or inside the recess. Clean up if necessary, is easy with a cotton swap with alcohol. We use denatured alcohol to clean up after epoxy glue and epoxy finish and just about everything else. We also use the denatured as our fuel in our alcohol lamps. You can use other chemicals, but be careful because some such as MEK and Acetone may blemish the finish on the blank.

You will have to clean off the excess epoxy off the blank in front or your grip. If you don’t have any glue to clean off, then the grip was too snug. I mark the blank where the grip will be placed because the reel seat with insert is the last thing I mount on the rod. We use the exposed butt section to clamp our drying motor. Also, it is less hassle when I’m wrapping and it weighs less and we don’t take the chance of marring the reel seat parts. Double check that your reel seat hood is aligned properly to your guide side marking.