I realize that I should have used turpentine or other drying agents
Turpentine doesn't really promote the drying of linseed oil despite many references to the contrary. In a woodworking context what it does is thin the mixture so that less oil is actually applied, and that obviously dries more quickly than more oil.
Is there anything I can do to speed up the drying process?
Provide plenty of air for the linseed oil to react with. Linseed oil 'dries' by oxidation and it needs air to do so.
Higher temperatures help quite a bit too, but the main thing is to ensure there's plenty of moving air going over the table.
Assuming you do nothing to the table but give it plenty of air the surface should be reasonably 'dry' in about a week (assuming all excess was wiped away after every coat as should be done). But expect it to take many months to be more fully cured.
Would sanding it again with a very fine sandpaper (grit 240?) help?
You'll probably clog the sandpaper fairly quickly but sanding will remove oil-saturated wood and what's left in the surface will dry more quickly.
Wiping off excess oil with a cloth lightly soaked in turpentine?
Yes again this will remove some oil from the table and what's left will then dry faster.
Adding a layer of beeswax?
No. This will slow the curing of the oil.
The problem with removing some of the oil is that you still need to oil further to give the table a proper finish. In my experience four full-strength coats of linseed oil are the bare minimum needed for a decent finish, and 7-10 is usually much better. With boiled linseed oil* this process takes as much as two weeks, with raw linseed oil I guess it could take 3-6 months!
*Not boiled but instead has metallic drying agents added to speed curing.