A dream of a great achievement can mean that you are expecting to achieve something important in waking life.
Alternatively, dreaming that you achieve something can mean that you feel that your plans always lead to disappointment and you never achieve anything.
If other people are celebrating an achievement of yours in a dream, you may want more recognition for your accomplishments.
Dreaming that a potential achievement is foiled can be a message that you are using the wrong methods to try to reach a goal.
If you dream that someone else achieves something that you wanted to achieve, you could feel that other people have more advantages than you do.