Arrrgghhh Castling!

It's important to note that strong attacks don't materialize out of nothing. Three basic ideas that signal you have good attacking chances:
More space on that side of the board (more space for you to maneuver simultaneously means less space for them to organize a defense).
More attacking pieces on that side of the board than they have defenders.
The center is locked with pawns. An open center gives more squares to defenders to post themselves, and also an open center gives counter attacking chances to balance your threats on their king.
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That said, two basic types of attacks come to mind. First is you use your pawns to open lines and/or remove the enemy king's pawn cover. Remember that if you attack one of their pawns with one of yours, and your opponent doesn't want to open lines, they will probably advance their pawn if it's safe to do so... so ideally you'll also control the square in front of their pawn so they can't avoid capture.
Second is you have 2 or 3 more attackers than they have defenders... so you can sacrifice pieces to remove the pawn cover.
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These are some of the basic ideas. To improve your attacking play you can solve mating puzzles to see some of the typical patterns. Once you're familiar with various patterns it's much easier to notice opportunities to build an attack in your own games.

It's important to note that strong attacks don't materialize out of nothing. Three basic ideas that signal you have good attacking chances:
More space on that side of the board (more space for you to maneuver simultaneously means less space for them to organize a defense).
More attacking pieces on that side of the board than they have defenders.
The center is locked with pawns. An open center gives more squares to defenders to post themselves, and also an open center gives counter attacking chances to balance your threats on their king.
---
That said, two basic types of attacks come to mind. First is you use your pawns to open lines and/or remove the enemy king's pawn cover. Remember that if you attack one of their pawns with one of yours, and your opponent doesn't want to open lines, they will probably advance their pawn if it's safe to do so... so ideally you'll also control the square in front of their pawn so they can't avoid capture.
Second is you have 2 or 3 more attackers than they have defenders... so you can sacrifice pieces to remove the pawn cover.
---
These are some of the basic ideas. To improve your attacking play you can solve mating puzzles to see some of the typical patterns. Once you're familiar with various patterns it's much easier to notice opportunities to build an attack in your own games.