The hardest part of speaking a new language is not the middle of a conversation. It is the first ninety seconds, before any rhythm exists. Learn a small opening and you never face a blank start again.
Learn four questions, not four hundred words
Where are you from. What do you do. How long have you been here. What brought you here. Those four carry the opening of almost any conversation, and each one buys you thirty seconds of listening while you settle. Learn the answers to all four about yourself too, said fluently and without thinking. Being asked something you have rehearsed is the fastest way to stop feeling like a beginner.
Say less than you can
Beginners try to say what they would say in their own language, fail, and conclude they cannot speak. Say the simple version instead: short sentences, present tense, no subordinate clauses. A conversation made of simple sentences is a real conversation. One abandoned halfway through a complicated one is not.
Rehearse your opening until it is automatic, then stop preparing. Everything after the first five minutes has to be improvised anyway, and that is where the learning happens.