The most difficult step will likely be finding an employer willing to hire you (many employers are unwilling to consider foreign candidates for jobs because the process of hiring them is so difficult).
First you should find out if you fall under NAFTA (see link below). If you fall under NAFTA, you won't need an LMO (labour market opinion) to get a work permit and this will make the entire process much easier.
http://www.cic.gc.ca/english/work/special-business.asp#nafta
If you do not qualify under NAFTA, this means an employer will have to obtain an approved LMO in order to hire you. LMOs involve a fair amount of paperwork and waiting - and an employer has to prove they couldn't find a Canadian for the job and therefore have to hire you. Additionally, not all LMOs are approved. Because of these complexities, many employers aren't willing to go through the LMO process or consider foreign candidates for jobs. More information about LMOs here:
http://www.cic.gc.ca/english/work/employers/lmo-basics.asp
Since you are from the US, you can apply for a work permit when you cross the border (assuming you meet all of the requirements for the work permit).
It's very difficult to say when you should start your job search and I think it will be difficult to time everything just right (because there are so many factors you won't be able to control). If you don't qualify under NAFTA, start looking for a job early. It could take many many months.
Hope this helps. Good luck.
