I'll be a Signal Officer, and I have an electrical engineering degree. Its not an Air Force trade, but it is the same process for any element. I also had applications in for Communications and Electronics Engineer (Air) and Aerospace Engineer, but I wasn't selected for either of those. I also considered applying for Pilot in the off chance I'd get it, but I realized that wasn't the best option for me, nor the best for the CF.
Tid bits are hard to provide without specifics (also with my lack of experience, I haven't gone to basic yet), but I'll just give some quick facts off the top of my head. Most of these aren't that useful to someone in your position, but sometimes its helpful to find out as much as you can about something, even if it doesn't apply to you right now.
I can tell you that selection boards (basically, the guys/gals who sit down in Borden and decide who gets offers) for DEO sit twice a year. Currently they are once in May/June, and again around October/November. That doesn't help you much now, but keep it in mind. I missed the last go-around last time, so I had to wait a few months for the last boards. Basically what this means in 4 years time is that about the same time you apply to your University to graduate (a common procedure at most schools, in your final year), you should be applying to the forces.
Obviously the standards are the same as anything else in the CF. Same fitness and medical standards. Those are well documented in a variety of places, so I won't go into detail.
This is a little premature, but its good advice nonetheless. If you do take out student loans for your education, one piece of advice is to keep them in check. You cannot join the CF with oustanding loans that are not being looked after. Its easier said than done (as I learned the hard way), but keep it in mind.
One good thing about the DEO plan is that you are paid as a 2Lt. while at basic. It's not a great big deal, but its one benefit. Also, if you're really lucky, there are sometimes recruitment allowances offered where you get a bonus after basic if your trade has signficant shortages. This is impossible to prepare for, as you can't go get a degree during the time they're offered, and obviously I wouldn't recommend getting a degree solely because you get a bonus later on. Do what you enjoy, and you'll be much happier.
Hmm, most of this stuff is pretty general to all entry plans and applications.
I suppose it wouldn't hurt to gain some leadership skills while you've got the chance. If this means joining a student club in your first year and eventually working into a leadership position, or joining a sports team or whatever, it helps. Not only will it help you personally, but it could increase your chance of getting an offer down the road.
Unfortunately one of the downsides of DEO is that you have to wait until after you graduate to really do much of anything (except for applying, of course). I inquired during my third year of University as to the possibility of doing basic officer training during the summer and then doing DEO after I graduated. I have sinced realized the logistical nightmare this would present, as well as the awkwardness of integrating into the further training plans. The ROTP officers are able to complete much of their training (Basic, and French Langauge Training) during the school year and in the summer's, so they have a definite advantage.
On that not, one thing you might want to check into is Civilian ROTP. You can go to school at a Civilian university instead of at RMC. I looked into this very briefly in my third year of University as well, but it was too late to be really beneficial to me. By going the DEO route, I'm now eligible for the recruitment allowance (basically, a $40,000 signing bonus) as opposed to them paying for my final year of school (which worked out better financially for me, I'd be stupid to reject the better option). As well, I would've been in approximately the same boat, as I'd only have had one summer for training, and I was told that very rarely are candidates accepted for ROTP that late in their University education.
I'm about out of information. Talking to a recruiter wouldn't hurt, although they couldn't really do much besides give you some basic information and tell you to come back in 4 years. Also, good luck.
Righty 
