You hear a sentence, convert it, think of a reply in your own language, convert that back, and by then the conversation has moved on. Everyone does this at the start. It stops not by willpower but by making certain phrases faster to reach than the translation.
Translation is a stage, not a fault
At the beginning it is the only route you have, and it works. It becomes the problem later, when the route itself is slower than the conversation. Telling yourself to stop does nothing, because the translation is what you have and the direct version is what you do not.
Build direct links for the things you say most
Certain phrases should have no intermediate step: greetings, the way you say you do not understand, how you ask someone to repeat, the twenty sentences you produce every single conversation. Drill those to the point of reflex, out loud, until the foreign version arrives before the version in your own language does. Every phrase you automate is one the translator never sees.
Attach words to things, not to words
When you learn a word for an object, look at the object. When you learn a verb, mime it. The aim is a link between the word and the world, not between two words. This is why pictures beat bilingual lists for concrete vocabulary, and why using the language while doing something physical works so well.
Notice, do not fight
When you catch yourself translating, that is a signal about which structure is not yet automatic, not a failure of discipline. Write down the sentence you were building. That list is the material for your next few sessions. Translation points at exactly what to drill.
You do not stop translating by deciding to. You stop when enough of what you need is faster in the target language than it is in your own.