Play at least 5 minutes every day, even if it’s just playing random notes for fun. Get in to a habit of playing more regularly.
Remember to keep good posture, sit on the edge of your chair with your feet flat on the ground
Re-print your band music.
Do path slides as part of your daily practice (just blowing through the range of the horn, getting all the inbetween notes and having your air move freely)
Here is an app that you can download to help you check your pitches: http://www.bandmatetuner.com/
Here is a fingering chart: ( 0 means no valves, 1 means index finger valve, etc)
Here are some exercises you can work on this week. Keep playing by ear as well, and have fun!