1. Get a phrasebook.
You can find a list of recommended phrasebooks here.
2. Download Anki.
Anki is a computer program that helps you memorise information. Think of it as your own personal assistant who is on call 24/7, incredibly efficient, incredibly patient, incredibly organised and free.
You can find more info about Anki, including a link to download it here.
3. Set up your Anki deck.
4. Learn 10 new words/phrases (on average) per day
Learn the phrases both ways i.e. from your target language to your mother tongue and vice versa.
Give yourself a deadline and stick to it.
5. Repeat until you have memorised the entire phrasebook.
6. Book yourself in for a standardised test.
Give yourself a concrete goal, and hopefully an internationally recognised qualification. You can find out more about this here.