I think that stock photos are very unique goods and you need some time and good promotion. Concerning affiliates - before you deal with them - check out their site and their business skills.
It deepends on yuor goals because big traffic sometimes is useless because you want to sell something and you must get only target audience for that. But I think that most important - is top 10 listing. If you are there - you will gain success )
Yep, Google likes fresh content and it is true that you have to update it constantly. If you are blogging you have to right fresg posts for 3 times a week... but I agree that you have to be careful with this strategy