Are you trying to select from what you already have or going to buy something new? If selecting from the items you already own I would suggest to do a try-on session and try on everything you have. This is what I usually do. Colors come in miriad of tints, shades and tones so even the most seemingly weird combination may work IRL. You can take pictures of what you think may work and post them here.
Your skirt looks almost olive on my screen (earthy muted color) and jacket is more of a pastel greenish yellow. I would be careful to pair them with any bright color as it can wash them out and make them look dirty and sickly. A safe bet is adding a neutral or another earthy or pastel color. I think anything warm should work: red, yellow, orange if it is not bright. Warm red-purple can work too in the right shade - like lilac and even lavender.
Sorry for the long comment - you can see I take colors seriously!:-)
