how to get good at mkx

Ive played mkx for around 30 hours and i have only played scorpion, jason and sub zero though scorpion hellfire is my main. And i know 30 percent combos and have memorized all of scorpions moves but I still can barely get any wins online even against other players who are 2-6 they completely destroy me by constantly attacking with safe attacks i couldnt even beat another scorpion hellfire player who was 2-3 how can i shut down or counter constant pressure and how can i get openings for combos?