The annual flowers will be much easier to start with. They must grow, flower and reproduce in one season, so they grow fast. Some perennials have seeds so small that they can look like a spec of dust. They will be slower to grow and it will not bloom as quick but it may live for many many years.
Basil is one of my favorite herbs to grow from seed. They have a unique feature that I always find fascinating to observe. If you place a few seeds on top on some dirt, then water well, in a short period of time you will see that they have formed a white jello-like coating.
Best to start with a rosemary plant vs the seeds, same with french tarragon. Parsley takes an extra long time to germinate for some reason.
Peppers and tomatoes are pretty much heat loving so if they are in a cool area they will take longer to germinate. A little bottom heat will help, like the top of the fridge, only till they germinate. Then they need light and lots of it.
I could go on and on.....
Oh, I do take the roots and about an inch of a green onion and plant it, works great!
:)