Don't use a flare leg, stick with bootcut or straight leg. Try a tall sock as well, (if the boots are taller) to put over the pant leg so there is less bunching.
Also, ankle length jeans work best, or if they are long, you have to put the hem under your heel when putting on the boots. Also get elastic leg bands from a sporting goods store. They are used for cycling to prevent your trouser legs from getting caught up in the chain, but also are great for keeping jeans tucked into boots.
i agree with tamerha...i've only seen it look good a few times and none of them were in real life. everytime i see girls on the street with jeans tucked into boots i think: yuk..what was she thinking?! unless your legs are a mile long, you can't look good in this style.
The boots also have to be fitted in the calf. Wearing baggy or wide boots like ugg boots tends to make the legs look shorter and thicker. A sexy high-heel boot fitted through the calf is the most slimming and lengthens the leg the best.
I personally love the look (on the right person with the right boots and jeans); it saves my jeans in the winter! You have to make sure that the jeans are very fitted at the knee, nothing looks worse than a big, baggy elephant knee over your boot.
Tucking your skinny jeans into a gorgeous pair of high heel form fitting knee boots is the best way to go because the heel in addition to the length of the boot shaft makes your legs look super long. Naturally this look really only works for women with slimmer legs. To make this look work you need to wear the right jeans...I prefer slim ankle cut jeans with knee socks worn over the jeans to keep them from bunching up at my knees. Finally, I like to wear form fitting sweaters and a leather coat to finish off the look!
First of all, I would skip the whole idea of using clips to hold the jeans in as someone else suggested here! Don't wear your usual bootlegs or sraight legs either because they will definitely bunch up at the knees. In fact, I was having problems myself until I found the perfect pair of jeans for Miss 60 and try on their their Eden style. It comes in different colors and they're perfect. The idea is to buy jeans that fit exactly like dancer's leggings. Not a good look without the boots, but once the boots are on you wont have to worry about bunching or jeans becoming untucked.
Hands down, the best thing I bought last winter were a pair of Stiruppz. They are like little suspenders for your feet. I used to hate having to retuck my jeans every time I stood up. They totally solved the problem. the website is stiruppz.com.