Lots of good advice. There seem to be several different approaches to this process. One is to do a major purge and then be so careful when you bring anything new into your home - for example-one in one out-that you never have the need for a big purge again. Another is to do it step by step, and know that it is like your closet-you will probably keep adjusting what you want to keep as your needs and desires change. One method says start with the easiest to let go of and one approach says start with the hardest and then everything else will be easy.
DH and I have done it in layers. First some stuff, then some more. You can start with an area that bugs you the most, or something easy. I found purging the kitchen knife and similar stuff drawer an easy place to start. I also found cosmetics, etc. a good place. I don't use the hotel or store samples, how many products did I think would de-frizz my hair, etc.
Sometimes what you need is a system. Why does X pile there? Could it be that putting an attractive storage piece there will solve the problem?
OTOH, don't spend a lot of money on storage or organizing items until after you have purged. And sometimes while purging you will find that a basket, etc. would be a great place to keep something.
I personally do not go by the idea that if you haven't used it in a year, it doesn't need to stay. I often use things a lot after not using them for a while. Same with clothing, jewelry, etc. But, I try not to keep anything that I know I won't use again, unless it is very sentimental. And then I put it somewhere I can enjoy it, or into a memory area.
Do leave enough time to put things away, whether away is your home, a donate pile, or the donation location. Leaving the house looking worse than when you started is discouraging, unless you know that you have scheduled time to finish it the next day, and you are okay with leaving it out until then.
If you can't figure out where to start, start where you are. Have 5 minutes while something is in the microwave? What can you do in the kitchen? The knives? You're at your desk-sort through your pens.
There isn't a right way, what works best for you is what's important.
A few things to keep in mind. Not in any particular order:
Don't let the perfect get in the way of progress. (Maybe I butchered this quote?)
You are what's sacred, your stuff isn't. Brooks Palmer.
Something that was given to you was a gift. As long as you've said Thank You, you've done your part. It is ok to get rid of it.
Good luck!