Halfway through a sentence the word vanishes. Most learners stop, apologise, and switch to English. That is the only move that actually costs you anything.
Describe it instead
Native speakers do this constantly without noticing. You do not need the word for ‘corkscrew’ — you need ‘the thing for opening wine’. The listener supplies the word, and now you have learned it in the moment you needed it, which is worth ten times a word from a list. Practise deliberately: pick an object and describe it without naming it. This is the single most useful speaking drill there is.
Substitute and move on
A less precise word that keeps the sentence moving beats the perfect word that never arrives. ‘Big’ instead of ‘enormous’, ‘go’ instead of ‘commute’ — nobody minds, and the conversation survives. Finish the sentence even if it ends somewhere other than you intended. A finished simple sentence is a success; an abandoned complex one teaches you nothing.
Keep a note of every word you had to talk around. That list is the most valuable vocabulary list you will ever have, because every word on it is one you genuinely needed.