Like everyone has said: take them out of sight, and then if you don't miss them, let them go. De-cluttering is good for the soul.
My advice:
1. TRY ON EVERY SINGLE PIECE OF CLOTHING before you even try to keep it one more year. You might be holding onto stuff that doesn't even fit or that you now hate. I forced my boyfriend to try on each of the 40 pairs of pants he said he "might" wear and he found he hated about 1/4 of them, didn't fit in another 1/4 of them, and kept another 1/4 as "backup" (I begrudgingly allowed this). He wears the remaining 1/4 on a regular basis.
As you try the piece on, if you hate the way it looks, feels, fits - let it go. Clothing should cover you and make you feel confident. Personal style changes, your requirements change, trends change.
If you think, "It's not so bad....I might wear this for X....", then think of the last time you DID X. Would you reach for that piece? Would you next time? My example: I had some old college tank tops that I thought would look cute with vintage-y jeans and a straw hat. Except then I remembered if I were actually going for that look , I wouldn't choose those items. They got donated.
2. Turn around the hangars for all the remaining items. You have 12 months to wear it and turn around the hangar.
3. Alternatively, pack it all in a big bag or suitcase. If you don't retrieve something out of the bag, it's gone.
4. Work on building a timeless wardrobe with mostly quality staple pieces, mixing in a few trends. I'm rather anti-mustachian about clothing, but it works to a degree because I have a pretty classic style with some cheaper trendier clothing purchased seasonally.