staring at a candle flame whilst focusing on breathing may help you to take a step back and be in the Witness, where you watch all your thoughts but don't react to them or have any sort of resistance to them...and when you notice that you are drifting off with those thoughts, simply re-focus on the flame and breathe some more...this will bring you back into the present.
Most peoples minds are so overflowing with thoughts that tend to be circular, that is, they are the same thoughts you thought yesterday and the day before...they just churn around and around in the monkey mind...let them churn, instead of getting frustrated that you are obsessing, try just taking a step back, and if you are able to hold that space for a while you may enter a sort of silence. It's not the easiest thing to do mind you, if it were I'm sure people wouldn't have difficulties with meditation as some do.
Let us know how you go if you decide to give this a try
