17 miles consistantly is a fair piece of real estate. My commutes have varied between 14-42 miles rt. The tips I've been able to collect over the years(25 in Feb)is to be able to do any emergency repairs. Learn how to replace your brake/deraileur cables on the road. Don't scrimp on your commuting equipment. Get the best bike stuff you can afford. Keep up w/routine maintenence. Drink more water than you're used to drinking. Eat like an athlete. Especially oats and brown rice. Fresh fruit and vegetables. Take a powdered protein supplement when you start riding 34 miles rt. If you find yourself w/a low frustration threshold take a day off. It's a marathon not a sprint. Read posts on the 'Touring' sub-forum regarding equipment as 135-170 miprwk is like being on tour.

Alot of this may sound cliche, but there's a reason. It's based on 200,000+ commuting/utility/touring miles almost all trial and error.

All of the advice on others' posts is solid. Especially the part about keeping clothes/shoes at work. My routine is to change clothes daily both upon arrival at work and again on the homeward leg. It's more comfortable and certainly more sanitary. I keep an array of deo, soap, talc, anti-fungal spray, toothbrush /paste and a towel along w/a week's worth of clothes brought in on Mondays. My lunch is brought in daily. My work clothes are taken home each night.

Anyway, good on you for taking on cycle-commuting. It isn't always easy, but it's never dull. All the best.