Some thoughts and comments:
1) It makes a difference as to what type of rub-on finish you're using. A rubbing oil or 'Antique oil' finish (which are basically diluted linseed oil or varnish) aren't designed to give a gloss or semi-gloss sheen...more like an eggshell sheen. If you're using a rub-on poly finish, applying multiple coats can increase the sheen.
2) A rubbing oil or 'Antique oil' finish usually isn't a durable finish, rather a softer finish that needs to be re-applied every so often to maintain it's appearance and function. The standard method was once an hour for a day (8 hours), once a day for a week, once a week for a month, and once a month for a year. Because this is a softer finish applying a more durable finish over the top usually isn't a good idea - a hard finish over a soft base.
What you can try is to add a bit (not more than 20%) of a more durable finish such as poly - in a semi-gloss or gloss, and apply a couple coats of this.
IMPORTANT - test this on some scrap that has been treated the same as the piece you're finishing. Use poly that has same base (oil or water) as your rubbing finish. Check to see that you have no problems with new coats bonding with the old. Let first coat set for 24 - 48 hours, then lightly sand with a 220 grit paper, remove dust and apply your next coat - repeat if desired.
3) With a rub-on poly finish one or two coats gives you the durablity you need. If what you used was a poly rub on, make sure it's had 48 hrs to set, then lightly sand with a 220 grit paper, remove dust and apply a coat of a diluted semi-gloss or gloss poly. Dilute to 2 parts solvent (oil or water -whichever is base of your poly) to 1 part poly.
Let us know how you make out
Bob "Boardman" Borders