The Everest Base Camp Luxury Trek is not a very challenging trek. However, if you are a novice, we recommend a few weeks of basic cardio and strength training.
Best cardiovascular training includes running on an inclined treadmill, swimming, and cycling. Start your training with shorter sessions and gradually extend them to longer sessions. This will help improve the efficiency of your body to utilize oxygen.
Carry a rucksack, focus on your lower body, and perform one-legged squats, stair climbing, and running exercises. This will help boost up your strength and prepare you for the weight you need to carry while trekking.
Try flexibility training to keep your muscles loose and relaxed. Stretches are important too as it helps to avoid injuries during the training sessions.