Trying to memorize new vocab while at the same time holding a conversation may be a rather daunting challenge. I would suggest carrying a small notebook where you can jot down new words so that you can later form flashcards or mnemonic devices.

If you're speaking to someone through the computer you can write down useful words phrases in Notepad for example, and review them regularly. I usually save mine to the desktop and look over them every other day or so.

You just need to practice it with someone regularly.That is the only way you can remember it.

Como outros tem falado, deve escrever novo vocabulario. Depois, nos estudos, voce pode repassar as palavras novas e assim pode integrar na sua fala!

I agree with Vignesh, You have to practice it regularly. And try to use that word in your next conversation with that person, or in the same conversation, if it fits meaningfully in the sentence.