First and foremost, consider the fabric. You want to go for 100% cotton or at least mostly cotton and only a little bit of stretch if any... this is essential if you want to avoid white jeans that look "slinky" and like jeggings. Plus, the more stretch that is added to the composition, the more chance that the fabric will stretch out unevenly causing bumps you won't enjoy.
Secondly, hold them up and do a see-through test. If you can't tell in the fitting room, bring them home and make sure they're not see-through. Also, skin tone undergarments will be better than white ones.
Consider your most comfortable fit and choose that silhouette. If you're a skinny jeans lover through and through, stick with skinnies. If you're more comfortable in a less form-fitting style, which feels exaggerated in white, then opt for a clean straight leg or even a high-rise bootcut for a streamlined look.
