Golden Crest said:

Heya! ~ I am still learning but with reflections I just go on the horses original layer, copy it and then paste it on a new layer. I flip it then position is in a spot that looks good - then play with the layers opacity. To include the mane, tail etc - I would suggest waiting until your piece is completely done, merge the layers then do the above. You can always merge, copy and once you have the copy, undo the merges and then paste the "reflection" horse :) feel free to message me if you need screen shots to show the steps <3