we found putting up flags/banners to be the best.

Where we live up North in summer, the hummers who nest there were drawn to our American flag that we put up.

They will of course come to flowers, but you have to GROW those, and
that takes time.

If you have ANYTHING bright red or yellow, to put up in the windows, that helps too. (I have some stained glass flowers I hang in my windows). You also have to replace the nectar every 4 to 5 days, to prevent mold.
Mold attacks the tongues of hummers and kills them. So in the beginning of the season I only fill 1/2 or less of the feeder, until they really start coming. You can't see the mold sometimes, so don't rely on visual appearance of it.

My hummers up North don't seem to learn that Petunias don't give much nectar. They come to them every day! I have some planters up on the wall along our porch where the deer can't get them. Hummers come to them all day long. And the new fledglings practice on them too. You can plant any really nice RED thing in a pot, and it will attract the attention of the hummers to your area, then they will find the feeder. Put the first feeder near the red plant you attract with to start. Once they learn you feed, they will remember. Ours come to and hover in the windows when we first arrive up North to remind us to put the feeders out! And if one goes dry, a little hummer will hover over my bedroom window so I can see her, and remind me! I was surprised at this, behavior. But I guess they are really smart!
90% of the their diet is bugs, you know, and they use the sugar more later in the season before they migrate.