From SuperCombo Wiki

Footsies is an archaic term for the primarily grounded component of the neutral game, played at mid-range, especially in Street Fighter styled fighting games. It tends to revolve around moving back and forth, and poking each other, usually with low cancellable normals (hence footsies, since characters tend to attack with crouching kicks). Sonic Hurricane has an advanced guide to a large number of specific footsie scenarios that can help make playing this component of the game more concrete. JuiceboxFGC also has a good guide to footsies that primarily focuses on whiff punishment.

The basics rules are, in the neutral game:

  • If you use a move that outranges your opponent's move, you will win, thus pokes beat jabs.
  • If you use a move that starts up before your opponent's move (either because it's faster, or you pressed the button earlier), you will win.
  • If you use a move later than your opponent's active frames, you can punish their recovery.
  • Attacks beat throws, because they have more range.
  • Throws beat blocks, because throws are unblockable.
  • Blocks beat attacks, because they prevent damage.
  • Up close, throws beat attacks, because they're faster than attacks.
  • Attacking extends your hurtbox, thus your limb can be hit if it misses, even by short range moves.
  • Jumping beats all grounded actions except anti-airs.
  • Jumping is reactable, so if you're doing nothing, you can react to beat jump-ins with anti-air.

These rules create the basis for the footsies game. Not all games necessarily follow these rules, because they might have additional mechanics that make the mid-screen neutral game different or make it occur less frequently.

This tends to create a flow of the game where people move back and forth, to get into a position where their pokes will work and their opponent's will not, and to deny their opponent the same. They try to poke at times when they think their opponent will poke or move forwards, and they try to stand just outside their opponent's poke range so they can whiff punish their opponent or counterpoke with something that goes around their poke. If they think their opponent isn't going to poke, they can take that opportunity to walk or dash into their opponent's face and either throw them, or hit them with move to start pressure. Otherwise, pokes keep your opponent out of your face, preventing them from starting pressure or throws.

Because of these rules, there are a few rock paper scissors triangles that result.

  • Attacks > Throws > Blocks > Attacks
  • Whiff Punishing > Poking > Moving into your opponent's space > Whiff Punishing
  • Waiting for your opponent to do something then punishing it on reaction > doing something pre-emptively to stop your opponent > Taking advantage of your opponent's passiveness to move in on them or set up > Waiting for your opponent to do something
  • Jump-ins > Fireballs > Anti-Air > Jump-ins

Try looking for other rock paper scissors triangles in fighting games, or cases where there are more than 3 options, which each beat your opponent's options differently, with different risks and rewards. These are common across fighting games, things that beat each other cyclically, with differing tradeoffs between each option. They form the basis for how you land hits on your opponents.