Brief Answer:
Please consider these guidelines

Detailed Answer:
Hello
I appreciate your concern
LVEF depends upon the contractile power of the heart and resistance in blood vessels

Here I would like more information for better assessment of the condition
Any history of smoking or alcohol consumption
Please upload me all the relevant investigation reports like ECG or echocardiography.
When did you get last attach and what was the interval between both.

Since you non diabetic or not obese so there are good chances to improve LVEF.
Complete abstinence of alcohol or smoking is required
Low salt and low fat diet
Aerobics and regular exercise which can be increased gradually
Continue taking medicines as your doctor has advised you.
Have good balanced diet with lots of fresh fruits and vegetables
Remain cheerful and try to avoid stress and anxiety

Please write back to with the details I have asked for, so that I will be able to tell you more accurately
Wish you good health

---