One of my fashion-related skills is packing light and packing well. For instance, I just went on a fairly long trip where I managed to fit everything I needed into a carry-on size backpack and my purse - and the fact that my load was light definitely made the entire experience more carefree and relaxing.
Here is my method (I usually set aside a few hours for packing as well):
1. Consider the reason for the trip - obviously, you will need different clothing for a professional/work type trip than you would for a vacation.
2. What is the climate and overall atmosphere/feel of the place like? - for instance, I'd probably take different clothing to say, Paris, than I would to somewhere more rural, or somewhere tropical.
3. Any special events - will there be a reason I need something formal? Anything else that might call for out-of-the-ordinary clothing? Any special accessories necessary? Make sure you pack those essentials first and foremost.
Now for the actual packing - I like to lay everything out on my bed or any other large flat surface, so I can see if the colors blend. This leads to my next point - I like to ensure everything I take can be worn as part of multiple outfits, which tends to mean I stick with one fairly neutral color family, e.g. blacks/grays/blues. Brighter colors and accents can be added with accessories.
For me at least, it's really important to see everything together like so I can edit out what doesn't belong. I tend to bring more tops than bottoms (a pair of jeans can be worn for more times than a shirt, usually) and I stick to darker colors, because they are less likely to stain. I also like to only bring one or two pairs of shoes - casual and dressy - simply because shoes take up tons of room. Same goes for handbags. However, I do pack lots of tiny/compact accessories like scarves and jewelry so I can mix up my outfits when I get bored.
I also try to edit down my beauty routine - I bring tinted moisturizer, mascara, one eyeshadow palette, and a lip gloss or two - and that is about it! Of course, sunscreen and essentials like shampoo are necessary as well, and if you travel a lot it is best to invest in a set of small containers you can fill up with your favorite products. Also, if you're going with friends or family, you might to consider sharing things like shampoo - not everyone needs to carry their own tube of toothpaste.
Last but not least, be sure to leave room for souvenirs!
Do you have any stellar packing tips? Share them in the comments!