Sati-Sampajañña (Mindfulness) Hello folks I have some questions on mindfulness.


How do I maintain mindfulness in stressed or high stimulus environments? It's easy at home and when I do my things alone but once I'm at work (delivering food on a bike), at school or being with someone it's very hard to stay mindful. Any suggestions? 
I couldn't really see any good explanation of buddhist mindfulness. If someone has an easy explanation please send me a link, however it combines alertness or concentration with a clear knowing what is going on (a label), isn't it so? But after an experience has been labeled it's not done yet. The practitioner needs then to do something to change from a unwholesome state/behaviour to a wholesome state/behaviour, right?
This question is related to the first one. If I am at work my mind is jumping from thought to thought and I feel in my body that I want to do things really fast. So in essence, my mind and body feels hasty and like a turmoil. Is there any practical advice how I can settle down the mind and body in in a fast way (especially when it's getting difficult or rather where distraction is available, e.g. at work, school, etc).
This is through maintaining Sati, Samadhi and Sampajanna it self.

1st one should keep your mindfulness in the 4 Frames of Reference. You should have Sampajanna in the following way:


  
  purpose (sātthaka): refraining from activities irrelevant to the path.
  suitability (sappāya): pursuing activities in a dignified and careful manner.
  domain (gocara): maintaining sensory restraint consistent with mindfulness.
  non-delusion (asammoha): seeing the true nature of reality (see three characteristics).
  


Source: Sampajañña also see The Four Sampajanna by VRI, Sampajanna by VRI, Sampajanna-the Constant Thorough Understanding of Impermanence by VRI,
 Sampajañña: The Fullness of Understanding - by S. N. Goenka, The Importance of Vedana and Sampajanna by VRI

Though arise due to sensory input. Perhaps you can try to restrict distraction by non reaction to the sensory input, which is to maintain the domain, and also be non deluded by at least seeing arising and passing nature of the experience. Also if the thought that district you are not related to the path you can abandon them. More on this see Vitakka Saṇṭhāna Sutta. Also be careful there is no lapse of mindfulness which might lead to unwholesome 
 or unsuitable thought to arise.

To quiet your active mind perhaps you can try out developing the Jhana factors. Saṅkhitta Dhamma Sutta. If initial and sustained application is developed within the 4 Frames of Reference this also you are keeping to the domain, purpose, doing what is suitable and non deluded, while also getting and handle on the distracting thoughts through concentration.

To apply this to daily activities always see it your mind is with the 4 Frames of Reference periodically, with initial and sustained application, contemplating the at least impermanence of the of the three characteristics, as you go through your daily activities.