For short and very inspiring videos, watch Joshua Becker on youtube. Choose the ones which apply best to you.
Start with easy quick wins. Take a rubbish bag and throw out pens that dont work (or simply that you dont like using), happy meal/party bag toys which are never touched, all those random bits and pieces which arent used.
Donate DVDs and books which wont be watched/read again. Even if you enjoyed them at the time. If they're not going to be used again pass them on for someone else to enjoy.
Go through DC clothes and get rid of* anything that is too small or verging on too small.
Go through your clothes and get rid of anything which is holey, stained or doesn't fit. Get rid of things that are in perfect condition but you just dont wear cos they aren't comfortable/don't suit you etc.
When are you moving? I did a massive declutter before moving last week and was so so grateful. Even so, i continued the declutter as I packed boxes.
*when I say get rid of I mean donate, recycle or bin depending on condition