First, sit down and have a serious conversation with your friend about why she just can't seem to get it together. There may be a valid reason behind her no-shows or tardiness - maybe she has a lot going on a home or she's bogged down with work.
Next, make it a point to treat your friend like the person who she is. That means not planning an important event with her that may go sour if she doesn't show up. This will spare you from disappointment and anger in the future.
Finally, speak to a live psychic if you are unsure of where your relationship is with your friend. Psychic readings can provide you with further insight into your friendships and let you know when it's time to move on.