Four in a row strategy
Four in a row is a game of threats. The player who holds the middle and makes two threats at once usually wins. These are the ideas that matter most.
Start in the middle
The board has seven columns and six rows. More lines of four run through the middle column than through any other, so a disc there helps the most lines. Take it early, and the columns next to it after that.
Every move opens a cell
Discs fall to the lowest free cell, so every disc you drop also opens the cell above it. Before you play, check that you are not handing your opponent a winning spot right on top of your disc.
Make threats, then a double threat
A threat is three of your discs with an empty cell that would make four. Your opponent has to block it. The winning trick is to make two threats at once, for example a row and a diagonal that share a disc: only one of them can be blocked.
Mind the diagonals
Rows and columns are easy to see; diagonals are where most games are lost. After every move by your opponent, check both diagonals through their last disc.
Think about later
Sometimes the best threat is one you cannot use yet, because the cell under it is still empty. Keep it: later in the game your opponent may be forced to fill that column, and then your threat wins.
Practise in Quad
Quad is four in a row against an AI that fights back, with three levels: easy, normal and ruthless. Two people can also play it together on one device.