I am guilty of not practicing for a few months. Now I have started again I find that my notes are wobbly, or tremolo. I cannot produce a continuous breath, it goes strong-weak-strong-weak. What can I do about it ?
Long tones build your embouchure strength.
Start with playing all the notes in your range for 10 seconds each day for one week.
Then play for 15 seconds each note, each day for one week. Then move to 20 seconds. etc.