I haven't begun yet this year, as we still have plenty of winter to go; however, I do have some pictures from last year.
The seedlings in the paper pots were started in re-purposed fruit/cookie/salad containers and needed to be pricked out first.
Shallow containers will work for frost hardy seedlings. You can get them out sooner. (The hanging plastic was to deter the neighbor's feral cats that kept digging in my seed trays!)
I used popsicle sticks for markers...just cut a tiny slit in the top of the handle and shove 'em in.
I kept my caps on to deter chipmunks and field mice.