Las causativas expresan que haces que otra persona haga algo: obligar, permitir o conseguir. El escollo aquí es qué forma verbal pide cada una. Make y let van con infinitivo sin "to" (make me study, let me go), pero allow, get y force llevan to + infinitivo (allow me to go). Y la de servicios, have/get + objeto + participio (have the car fixed). Memoriza cuáles son "sin to" y ganarás naturalidad.
Make / let vs allow / get
ENmake + person + bare infinitive (force): He made me wait.
ESmake + persona + infinitivo sin "to" (obligar): He made me wait.
ENlet + person + bare infinitive (permission): They let us leave.
ESlet + persona + infinitivo sin "to" (permiso): They let us leave.
ENallow / get + person + to + infinitive: She allowed me to go.
ESallow / get + persona + to + infinitivo: She allowed me to go.
ENhave + person + bare infinitive (arrange it): I had my assistant call you — but I got my brother to help.
EShave + persona + infinitivo sin "to" (encargárselo): I had my assistant call you — pero I got my brother to help.
Encargar un servicio
ENhave/get + object + participle: I had my hair cut.
EShave/get + objeto + participio: I had my hair cut.
ENget + person + to: I got my brother to help.
ESget + persona + to: I got my brother to help.
El error típico del hispanohablante
Nada de "to" tras make/let: make me go, let me go — no "make me to go".
Pero allow sí necesita "to": allow me to go.