First, sit down and make two lists: the HAVE to have list, and the NICE to have list.
Figure out how to pack the essentials in whatever pack you're using, then you can decide what non-essentials you can take, if you want to.
I'm not really hard core about stripping ship to the bare sticks, I'll take along a good bit of "nice to have" stuff as long as I don't feel overloaded.
Compression sacks are great for saving space. Since I use a "gasp :tinysmile_aha_t: " external frame pack, I strap my tent/sleeping bag/sleeping pad on the outside, leaving the inside of the pack for other stuff.
My biggest flaw right now is carrying too many extra clothes. I'm getting better at judging that , though.