Notes on this puzzle
Skyscrapers #5308 is a 6×6 city: every row and column holds the heights 1 to 6 once, and 11 of the 24 edge positions carry a clue. 5 heights are already standing inside the grid.
There is 1 clue of 1 around the frame; the first cell beside each of them must hold a 6. The top edge carries the most clues (4). 13 edge positions are blank, so parts of the grid are solved from the inside out.
Where to beginTry row 6, column 6 first: its row and column clues decide it without any other help. Check every pair of opposite clues; a pair adding up to N+1 is a gift.