@Pat, good first try
To become as good as Diego and Issabella, we will have to practice a lot and for a long time, I think

Ella, I find "old books and candle" to be outstanding! I love it how it has come out and perfect about saturation, too. Congrats!

Isabella, Ella: you have reached the top in rendering the mosaics.
Graduated with first class honours!!!

It's a long and (sometimes) frustrating flow, but when such masterpieces are finally created, I'm sure you both have a great satisfaction in your (artistic) heart.

Thank you Dinasset. You are very kind.

Thank you, Diego, for the positive comment.

There are still a few things that don't always work out well.
Finding the right photo, knowing which color of mosaic fits best, sometimes there is little color difference.
You only notice the result after merging down with the texture layer.
And if the result is not good, you have to start all over again.
Also the border lines are often too close together so the details of the picture disappear too much.

So indeed I spent a lot of time making these outcome and sometimes I get frustrated
But if the effect and the comment(s) are good, I'm happy
I suspect the size of the picture also plays an important role.

@Issabella, which size have the photos you use?

Ella,
I know the flow is somehow "irritating"; for one point I can give you a little help (the selection of the appropriate pattern in the group you chose).
Follow me:

========================================================
1.Use the Color Picker Tool on the area
This will set the Foreground color (att.1)
2.Click on the Foreground color to open the color selection dialog
In the open dialog you can see the value of the Hue (att.2)

Each mosaic patterns set has a value for all hue values at interval of 30, identified by 3 chars:
000 = Red
030 = Ora
060 = Yel
090 = Cha
120 = Gre
150 = Spr
180 = Cya
210 = Sky
240 = Blu
270 = Prp
300 = Mag
330 = Slm
Choose the pattern with the closest Hue value (or in any case close to the area hue)
In the example : choose the pattern suffixed with Gre which is for value 120, very close to 116.1

But check whether the area color is gray (all values of Red,Green,Blue very close each other (att.3)
In this case choose the pattern suffixed with Gra

Hope this helps you a bit.

Thank you Dinasset for your helpful tip.
Ella, my preferred size is 1280px

Thank you so much Dinasset, for your nice new patterns.
My first tries with the new patterns (not so good as yours)

Thanks for the explanation, Diego and Issabella. I copied it and attached it at the tutorial.

Issabella, you started embroidering, weaving and knitting

Thanks Ella. I enjoy the process a lot and now with a few more patterns. Thanks again, Dinasset.

So many wonderful outcomes!

@Pat, I don't know what you imagined, but I like your flower. You'll become even better with practice, too.

@Issabella, your cranes rock!

I tried to combine the old effect with the mosaic effect. I didn't quite follow through the mosaic effect as for my purpose on this image the achieved level was sufficient.

Interesting thing - since I upgraded to 2.10 the old effect works - I had a hard time on it with 2.08. There was still another tut that I need to revisit with 2.10, only at the moment I don't know which it was

Moniaqua, thank you for your comment and encouragement. I like your amaryllis, also. So many ways to make a beautiful image with GIMP!
Ella, very nice with the girl and lilies.

Monika, what is the "old effect" you mentioned?
Ella, it looks like a real mosaic.

Bad English
I meant this tut: viewtopic.php?f=10&t=17246&start=0&hilit=revisited+old+effect
On Gimp 2.08 there was some filter missing in my setup or working differently, so I had to work around. I never got the pics looking really like the samples in the thread. This is easier on 2.10.

Oh, I see.

Always beautiful outcomes
to all participants

Moni, it's great that you have tried this new mosaic effect. I hope many others of your results.
Ella, I love the skin hue you got in your last outcome, also the black look. A great result.

Pat, dinasset, level_10 and Issabella, thank you for your comment.

Thank you, Issabella and level_0

level_0, what a wonderful new avatar!

Ella Louise, that teapot fits perfectly to the method.