Its a common problem for beginners, and you're right, it just takes practice. One thing that can really help is the "divide & conquer" approach... add one finger at a time, making sure all the strings play cleanly as you do. When you add a finger that causes the problem, correct it and continue. It takes time to be able to fret chords cleanly and effortlessly, but you'll get it, so long as you practice cleanly. Practice slowly, making sure you're getting it right. If you try to rush the process, and practice sloppily, then that will come out in your playing, and it'll take longer to correct than if you just had practiced slowly and cleanly. So while taking it slow at the start may seem like the long way around, its actually going to be the fastest process to getting to be able to play the chord cleanly.