One of the biggest tricks my guitar teacher showed me many moons ago was to practice the chord shapes while ensuring there is space between the the bottom of the neck of the guitar and the bottom of your thumb (where the thumb meets the palm of your hand). Enough space for you so fit a pencil through. Do this with your thumb flat on the middle of the neck. If you guitar has a line on the back of the neck then follow that. Also ensure that the top of your fingers are placed on the strings while in this shape. Over the course of a couple weeks if you practice often youl build up a lot of muscle in your hands and fingers. Warning: your hands are gunna hurt and get tired fast. The chords will still not sound great either. But entually once your finger and hand strength increases and your muscle memory kicks in youl be killing it in no time. Best of luck!