Its very important that a straight skirt fits correctly or it will look and feel awful, and if it doesn't feel comfortable you won't like it.
Women often make the common mistake of wearing them too tight or too short. The skirt should fit snugly on the waist, but it should be loose on the hips. When you are stood with your legs together the skirt should be hanging from the waistband and not gripping your hips.
If the skirt is tight on the hips, several things are likely to happen. The skirt is liable to rotate when you walk, or the lining will ride up and bunch up underneath the skirt. Remember a straight skirt will ride up when you sit in it and if it's too tight on your hips and thighs, it will stay ridden up when you stand up.
A skirt that fits correctly falls back down again under its own weight. You won't want to keep having to pull your skirt down every time you get up.
Make sure the skirt is the correct length for you and that you are not wearing it too short just because everyone else in the office is wearing them that length. I like to wear my skirts almost calf-length in the winter.
Most ready-to-wear skirts come with an open back vent which goes halfway up the back of the skirt, but this is totally unnecessary, especially if the skirt is knee-length. I convert all the back vents in my RTW skirts into a knife pleat, and if the skirt has plenty of ease I just close up the back seam altogether. It makes the skirt much warmer in the winter. If you wear a straight skirt often you soon get used to wearing them without a back vent.
If you wear a straight skirt with high heels it will be easier to walk in than if you wear it with flats. This is because high heels encourage you to walk from your hips and not your knees. It's difficult to walk from your knees if you have a tight skirt around them.
Finally, if you are new to pencil skirts, take your time to get used to wearing them; they are a bit of a shock if you've been wearing trousers all the time.