It is no secret that standing open in your set up will promote an out to in swing which in turn will give you that dreaded distance sapping slice.
So make sure that your set up and alignment are spot on ie place a club along your toe line and make sure that it is running parallel, like rail tracks, with an imaginary line from your ball to the target.
Initially you can even exaggerate this to fix your slice by standing a little closed ie with your right foot drawn back behind the left so that the line would be pointing right of the target.
Secret 2 - Get a proper grip
For many starter golfers and even more accomplished players the grip, if it is too weak/neutral, can mean that coming in to impact your clubface is wide open..not square which will lead to a slice.
Consider using a strong grip until you have rid yourself of the slice. By this I mean with your hands turned more to your right shoulder. This should encourage the clubface to square up earlier in the downswing and produce a ground gobbling draw.
Secret 3 - Swing from in to out, not out to in.
If you can imagine the face of a clock superimposed on the ground in the hitting area with 12 o'clock at the end where the target is then rather than aiming to swing from 6 o'clock to 12 o'clock, try swinging from 8 o'clock to 2 o'clock.
This will have you swinging from in to out, rather than out to in, giving you a powerful draw.