my advice? Take it step by step. I remember the Open F & B full chords being the hardest.

Start with your index (first) finger on the high E & B string 1st fret, pick the strings to ensure they ring clearly then add your middle finger to the G string, 2nd fret then stop. Hold the position, make sure your fingers and knuckles are arched (at an angle) and strike the strings individually to hear if they're ringing cleanly.

When you're confident with your ability to produce the above correct notes, then add your ring finger to the mix at the 3rd fret D string. Practice slowly and don't worry, because your hands and finger tips will strengthen naturally the more you practice :)

Remember, the F & B Major chords are the hardest, so add one finger at a time, perfecting the angle of your fingers!