You can set special priorities for certain jobs if you want them to get assigned first.
To do this you can use the Dispatch Console directly when you are creating a new job. Scroll down to the Extras section and under Priority select a level. It will go from 1 to 5, 5 being the highest priority (jobs with priority 5 will get assigned before all others).
When a job with high priority is booked, it will get assigned before the other ones and you can even choose to have it block other jobs until it gets assigned (the other jobs will appear with dark grey background in the Dispatch console).
To learn how to assign a priority level to a specific customer account, please click here.