No "proof of ties" to Canada... Help?

I was refused entry to the US, because the border guard decided that I didn't have sufficient ties to Canada. I had just returned from 6 months in the US, just traveling & visiting friends there. This trip, I was going to be taking a certification course that is not readily available in Canada. While it is an internationally recognized certification for the industry I want to be involved in, it is not a "legal" or required certification.

My questions are:

Should I just go to the closest US consulate & ask them how I can enter the US?
Are "proof of ties" arbitrary? As in, does each official decide on their own what's sufficient? Or is there a standard?

The guard I dealt with told me to "get a job or something" to prove my ties to Canada. The point of getting this certification is to do just that! So frustrated.

the fact that you just returned from being in US for 6 months weighs heavily against you. You clearly do NOT have much ties in canada iddf you were now going back.

If you really want to study in US, you should have the institution giving the course sponsor you for a student visa. You would still need to maintain a foreign residence, bu the ties need not be so strong.

What these officers are concerned with is you spending 11 months of the year "floating" around the country.