If decluttering is overwhelming to you, start small.
For example, if you're decluttering clothes and can't bear to part with all your "small" clothes or "large" clothes, don't get rid of all of them. Select a few outfits you really love, in case you change sizes. Just don't keep them all!
Or, if you're decluttering books, start with one shelf. See if you can get rid of half of the books on that shelf. Ask yourself, am I going to read this again? Would someone else benefit from it?
Don't feel you need to tackle your entire decluttering job at once. Start small!
Remember, you want to surround yourself with possessions you love. Do not let your clutter overshadow your beloved items and make it so you cannot enjoy them.
More on decluttering:
Three Steps to Decluttering