It is very difficult to clean a mirror without leaving streaks. It involves using just the right amount of cleaning spray on a completely clean cloth.
My mum's generation would often use yesterday's newspaper to wipe their mirrors with fantastic results. Something in the texture of the paper and the way the ink was made left their mirrors looking perfect every time.
The bad new is that newspapers now use completely different paper and very different ink. So if you try it now, you will likely end up with a very cloudy and smudged result.
Another thing to avoid is toilet paper or paper kitchen towels. They tend to leave flecks behind. It is also quite wasteful.
I like to use two Linen Cloths to do this. One for the initial spot-cleaning and one for the final polish.
Start by looking over the mirror for marks that will need particular attention from things such as hairspray or toothpaste. Hold the nozzle of your Scented Vinegar spray quite close to them for a direct spray then wipe away with your first Linen Cloth.
Once they are all cleaned away, move the nozzle of your Scented Vinegar further back and apply a very light misting across the whole mirror. Wipe dry in a vertical motion with the clean cloth.