I read that if you put everything in the closet with the hangers facing one way, but when each time you put things back in the closet after cleaning or in the case of a coat of a blazer you don't clean after every use, after wearing, put it in with the hook facing the other way. Then you will truly know what you wear and what you don't wear.
I have heard that if you don't wear it for one year, it is a good rule of thumb to get rid of it. However, I don't agree with this 100%. Sometimes its good to hang on to some nice pieces, and then you can "go shopping in your closet" each season and see what can be can be repurposed or will look unexpected without, say the matching pants.
maybe that is not much help, but here are my tips
These are two totally seperate methods and pick whichever works for you. the first one is messier but may be more telling
instead of focusing on the "get rid of" - focus on the "keep' if it is mentally easier. This may take up some room, because you will have to move everything, but it helped me. its kinda like "survivor"
Take all your clothes out of the closet and put them somewhere else - on teh bed in the spare bedroom, a wardrobe, box, whatever. make sure you don't do this when you are expecting house guests.
Now put these things in your closet.::
= If a garment flatters you - not just merely technically it can get on you - put it in your closet.. If it is a color that makes you look vibrant, beautiful, and it is the right cut for your figure, keep it. Now, be honest! for example, no matter how much i like this khaki colored dress that kinda has a crocodile hunter air to it. it makes me look ill, and also makes me look like a munchkin.
remember, we are not eliminating at this point, we are focusing on weeding out the "all stars" only sensational will apply here. remember, you are not thinking about what you are getting rid of here. AND BE LABEL BLIND.
= a pair of each color of socks - black, white, brown, pink - whatever you have. ditto on the pantyhose/stockings/garters
=7 pairs of panties/bras = but only if they fit you and are in good condition and make sure you have a variety fo colors for different outfits . ditto on any other underthing like camisoles.
= a pair of jeans - no holes - that fit you well. so you aren't raking leaves in a 50s wiggle dress lol.
= a pair of shoes in good condition that when all is said and done, you find yourself grabbing day after day to wear because they go with so much and/or are comfortable. for me, these are my black patent leathers driving loafers. i find they are comfy in MOST circumstances and go with a ton of things.
also in the "keep" pile= allow yourself a sentimental favorite. wedding shoes, the sweater from high school, the hat your gradnfather gave you, etc...
Now, get dressed everyday. just with what is in the closet. no fair getting other things from the other room because you didn't do the wash. Now, say the next day comes and you are invited spur of the moment to a summer outdoor bridal shower in a tent on a lawn, and afterwards someone else's pool party. You already have the most flattering, best fitting bathing suit in the closet as well as your most flattering dress and a few skirt choices. But, you can't wear your pair of shoes. say they are my loafers. the leather soles just wouldn't cut it at the pool party. so think for a minute (no peeking in the other room!) what would be the perfect shoe you would need? Say you pick a certain pair of sandals that can do both events, plus a belt for the outfit- now go in the other room and add them to the closet. You also add a sun hat - JUST ONE! and think about it before you just "look to see what you have" and of course, you found you had a run in a particular color of stockings, so go in the room to bring out a replacement.
so, basically the rule is, when you really need something and what you have there cannot perform that function, that's when you can dive into your other stash. and the other rule is you can't stand there in front of your stuff deciding it. if its an item you can't think about off the top of your head, than it isn't important. and of course it is also like "going shopping"- only with your stuff.
What you will see happen is that there is major room created without having to suffer - the duplicates and triplicates of things that are duplicated unnecssarily disapper (i was surprised that i really did have 14 pairs of black shoes and i really only wore four - i kept my patent loafers, a pair of pumps, sandals, and a funky pair of special occassion shoes that have always loved to wear - and do when the time arises) I was shocked that i had THREE pairs of those 'in between a loafer and stacked heeled pump" things from the 90s. what WAS i thinking?
what also happens, is that piece you now realize you have to constantly wash because you always wear it several times a week - when it comes time, get a duplicate of that, or you know what cuts. etc of clothes to look for when you do buy again without having to wonder will i actually wear this? i know there are things that i would love to buy, but then i have to really assess if i would actually wear it.
I found that some of the stuff i kept - instead of all these black cocktail dresses that i wear once and take up space, i have kept a few really flattering pieces that i can interchange to wear to the same occassions, and can change up the look and many of them due quadruple duty. I am never stuck having to shop last minute for an event, and can never be accused of wearing the same dress everyday either.
Anyhow, after you have a new set of eyes, you can divide the rest into what to donate, what to resell, what to pitch, and what is damaged but the fabric is worth salvaging (but only if you have a use for it - decorative use, to help alter the matching dress you kept that does with it. If you aren't going to use it - give it or sell it to someone that does. That would be the first thing that a lot of books tell you to do - put things in boxes, but i found it impossible for me without doing the above. i would rationalize too much.
Keep it in the mindset that this stuff CANNOT be kept, at least by you. maybe it is a dress that you can't wear but put it in your closet because your mom did (and it has no value as a vintage piece, lets say). If you can't bare to part with it, give it to a sibling or other relative who appreciate the connection.
I say keep that mindset, because inevitably, there will be items that you mend the rules on, but if you start out that way in phase two, it makes things easier. and oh yeah $$$ also motivates if there are things you can consign/sell or write off as a donation. i know the space and lack of clutter are probably worth zillions of dollars more of course.
PS - i almost forgot....it is easy for me to forget because i live in a 2 maybe 3 season environment...also put your winter coat you absolutely love and looks good on you in there, and continue the process as the weather changes.