My first suggestion is to start listening more closely to chord sequences that you like in songs. Be that on the radio, from your own collection, spotify, itunes etc etc...
At first take simple pop songs that only use 3 or 4 chords, loop them, and then learn the melody of the song so you can play it over the top of the chords. This is going to start getting you familiar with the kinds of melody notes that are available over certain chords. It will also give you a good idea of where your own taste in melody lies, and what combinations of melodies and chords sound the best to you.
Starting simple is the key here so that you can train your ear to hear small pieces of musical information at a time. Then it's a question of taking all these small pieces of information that you're learning each day, and putting them together to make up a bigger picture. Take it at your own pace and don't start with anything too complicated.
Your best course of study will be to immerse yourself in what sounds good, listen to that over and over, copy it, repeat it, and then take from it what you think is hip to add to your own vocabulary.