I just listened to your mix. And here comes the feedback 😀
A few times the melodies clash in a way that is really noticeable. I don’t think it is bad thing if that happens sometimes, but maybe try some harmonic mixing. Keep working on your beatmatching. you’re mixing is sometimes to much off beat. Look that happens, but in a promo mix you should try to avoid it. You can also do a second take, or a third one, or a fourth one. I know because I ‘ve been there myself 😀
The length of the mix is good. 30 minutes is perfect length for a promo mix. The mix is good as a promo. By witch I mean that it feels as showcase. It paints a picture of who you are as DJ. The build up is good. A nice variation of melodic and harder tracks. You also did a good job of putting 12 tracks in 27 minutes.
All and all a good mix with some room for improvement.