Our visa (Secondary teacher) was granted a few weeks back and we didn't use an agent. As long as you make sure you are really organised you should be fine. hardest bit seems to be getting the skills assessment under the new system. Make sure you have all of the documents you need before you start anything, send off for full copies of birth certificates, transcripts for each year of your nursing training (if needed, I did for my teaching-uni then teacher training inc hours of teaching which year groups in schools which was the hardest bit to get hold of), then get all of these certified. Set up a folder with originals and duplicate copies of everything you need and make sure you photocopy the final form before you send it off.
If you need extra points IELTS is a good idea but make sure you practice! It's harder than you think! The actual visa lodgement process is quite easy and all electronic.
If you are 100% accurate on everything in the skills assessment and expression of interest then its quite straight forward once they come back.
Good luck and shout if you need anymore help!
