Hey Rodeno.. as others have said.. invest in a hydrometer. Once you have it, check it against distilled water at the proper temperature. Some hydrometers are set at different standards than others. All of mine are at 60*F. The next thing that would be good for you to know is..
1. What
should my Original Gravity be? (OG) You'll see OG and FG in the discussions.
2. What
was my OG?
3. What should my Final Gravity be? (FG)
4. What is my current gravity. Is it close to what it should be?
If so.. even if there are no bubbles.. as UNIONDR mentioned.. let it sit for another few days to clean up byproducts created by the yeast beasts. If it's not there.. let it go for two more days to see if it drops. If it doesn't drop it may be complete and just won't hit the expected FG. Could be for a number of reasons.
So, that's the story on a hydrometer. Hope it helps.. there are good references online about these critters..
HERE is a pretty self explanatory video on YouTube