To create a good (i.e. actually useful) bot you want to start by spending a lot of time in whatever game you're targeting.
Most bots, or trivial helpers like macros, are written by the players that have spent a lot of time in a game and identified the elements most worthy of automation. The player's lack of in-depth technical knowledge then leads to the mass of crappy bots out there.
If you're coming from the opposite side, i.e. you have technological knowledge but don't know where to start, all you're missing is domain knowledge of an individual game or genre to figure out what you actually want to build.
Edit: it's also worth noting that game AI and bots are pretty different problems.
Most bots, or trivial helpers like macros, are written by the players that have spent a lot of time in a game and identified the elements most worthy of automation. The player's lack of in-depth technical knowledge then leads to the mass of crappy bots out there.
If you're coming from the opposite side, i.e. you have technological knowledge but don't know where to start, all you're missing is domain knowledge of an individual game or genre to figure out what you actually want to build.
Edit: it's also worth noting that game AI and bots are pretty different problems.