Checking with a hydrometer is critical if you're bottling. You want to avoid bottle bombs.
It helps to know where your FG endpoint will be (hence the FFT)--this is the best way.
A cruder way is to use the BeerSmith FG estimater (which I know some people on the forum hate).
Get your reading. If they match up within a point or so, then you can use the tables that show how much sugar to add to the bottling bucket (or to the individual bottles) to get a certain number of volumes of CO2 in the beer.
If they don't, then the best thing is to wait a few more days. Perhaps even raise the temps a few more degrees (get it warmer) and/or re-rouse the yeast gently (avoiding oxygenating the beer) with a swirling action.
I recommend planning ahead and giving yourself plenty of time to brew and bottle your entries, but, if you "have" to bottle today (let's say you're sending it off for a comp that's being held this weekend or next), then I figure that each gravity point adds about 0.6 volumes of CO2 to the 0.9 volumes of CO2 already in the fermented beer. For example, if I had an APA with a SG of 1.018 that I knew would finish around 1.015, then I would add no priming sugar and go ahead and bottle it knowing that it should end up around 1.015 (and with 2.7 volumes of CO2), since the bottle stays warm during shipping and handling to the site, as well as during the organizing and labelling phases of the competition. It gets chilled a few days prior to comp and you're good to go (and more importantly, you get no bottle bombs which may have occurred if you had added enough priming sugar to give 2.7 volumes + the 2.7 volumes from wort to yield 5.4 volumes of CO2). Again, I would only do this shortcut if you know where your beer will end up. I've been burned on this shortcut with a saison where the FG kept going into the single digits. There were a few gushers. I don't recommend this be a routine practice, of course.