A good first move is one you can explain. You don’t need to see the whole solution, just one cell where the rules leave a single possibility. Here’s how to find that cell in each family.
Read the fixed clues first
Before you touch an empty cell, look at what you’ve been given. On a Binary board, two fixed circles side by side mean the cells at either end of them can’t be circles. A bar or a cross tells you whether two neighbours match. On a Paths board, a wall next to checkpoint 1 might leave it only one way out.
Try saying the reason out loud: “This has to be a diamond, because three circles can’t sit together.” If you can’t finish the sentence, leave the cell alone and look somewhere else. The first empty cell you notice doesn’t have to be your first move.
Look where options are scarce
A clue with few options left is worth more than a big open area. In Light Up, compare a numbered wall with the free cells next to it. In Rectangles, list the sizes an area clue could take and cross off any that run off the board or swallow another clue. In Blooms, look for a row or region with only one cell left that could hold a flower.
In Ribbons, an endpoint tucked into a corner has fewer ways out, though its ribbon still has to leave room for every other pair and every empty cell. In Bridges, an island with just one reachable neighbour has to connect to it, and its number tells you whether that’s one bridge or two. In Mini Sudoku, find a row, column or box that’s nearly full and work out where its missing numbers go.
One move leads to the next
A certain move changes the board around it, so look there next. A Binary symbol affects its row and column. A Blooms flower clears its row, column, region and neighbours. A Light Up bulb lights a line of cells and rules out other bulbs in its sight. Follow that chain and you’ll often find the next move without guessing.
If nothing seems forced, check whether one of your notes is really just a hunch. What to do when you’re stuck has a short routine for that. If you’re still stuck, Hint will show you a next move or point to an entry to rethink.