How to email without it marked as spam?

I emailed my info and attached my video for my audition. I wanted to make sure that they'll get it, so I forward it to my other email. However, when I check it, it was in my spam folder. I was wondering if they company will receive it as spam also or is it just because I forward it? What should I do if they most likely received it as a spam?How to email without it marked as spam?
Your mail goes into the spam box, because it has the look of spam; and if that is the case, there is nothing you can do, but hope they check their spam box frequently.