If you're talking about the cue you play with all the time, I'd have a pro do it even though I've put on tons of them. The difference is I had the proper tools at the time and don't now.
You need to get the ferrule perfectly flat and clean, and the ferrule needs to be looked at to make certain it is still good. Sticks for kids to knock balls around with might be different, but my cue.
I want done right, and I like a soft tip for my shooter, and a hard tip for a break stick.
Get yourself a Mueller's catalog and order a ferrule grinder. This will fit on the shaft and have a grinding wheel attached that will allow you to get the ferrule flat and clean.I use gel type super glue. Scuff up the bottom of the tip with sand paper and glue both surfaces. Allow to dry a little, and then apply tip and I always then inverted the shaft with the tip down and applied pressure for about a minute.
Set aside and wait a couple hours or so and then shape up the tip. Interestingly to me, most of the really good players were not satisfied with their new tip until you sanded off about half of it.
By the way, be careful or you'll get glue all over!