There was a question and I felt that a small post on this would be useful. You can charge a black thread with intention and tie it on your body. It is a sort of an amulet. This is how you do it.

• You will need about 1m black thread. Choose one which is neither too thick or too thin and can be knotted securely. 
• Do this on an amavasya (ie a no moon day) or any Tuesday or Saturday is also acceptable. 
• Do this after you get ready in the morning. Sit in front of your deity, light a deepak, incense etc, do your daily puja as per your schedule. Specifically pray to your deity for protection.
• Then hold the thread in your hand, intend that your deity will now protect you with this thread.
• Mentally recite the Durga Saptashloki from the Devi Mahatmya. There are 7 shloks in this.

॥ श्रीदुर्गासप्तश्लोकी ॥
ॐ अस्य श्रीदुर्गासप्तश्लोकीस्तोत्रमहामन्त्रस्य । नारायण ऋषिः । अनुष्टुपादीनि छन्दांसि ।
श्रीमहाकालीमहालक्ष्मीमहासरस्वत्यो देवताः । श्री जगदम्बाप्रीत्यर्थ पाठे विनियोगः ॥

ज्ञानिनामपि चेतांसि देवि भगवती हि सा ।
बलादाकृष्य मोहाय महामाया प्रयच्छति ॥१॥

दुर्गे स्मृता हरसि भीतिमशेषजन्तोः स्वस्थैः स्मृता मतिमतीव शुभां ददासि ।
दारिद्रयदुःखभयहारिणि का त्वदन्या सर्वोपकारकरणाय सदार्द्र चित्ता ॥२॥

सर्वमंगलमांगल्ये शिवे सर्वार्थसाधिके ।
शरण्ये त्र्यम्बके गौरि नारायणि नमोऽस्तु ते ॥३॥

शरणागतदीनार्तपरित्राणपरायणे ।
सर्वस्यार्तिहरे देवि नारायणि नमोऽस्तु ते ॥४॥

सर्वस्वरूपे सर्वेशे सर्वशक्तिसमन्विते ।
भयेभ्यस्त्राहि नो देवि दुर्गे देवी नमोऽस्तु ते ॥५॥

रोगानशेषानपहंसि तुष्टा रुष्टा तु कामान् सकलानभीष्टान् ।
त्वामाश्रितानां न विपन्नराणां त्वामाश्रिता ह्याश्रयतां प्रयान्ति ॥६॥

सर्वाबाधाप्रशमनं त्रैलोक्यस्याखिलेश्वरि ।
एवमेव त्वया कार्यमस्मद्वैरि विनाशनम् ॥७॥

ॐ

If you cannot recite it then you can also listen to it. But do try to learn it, just 7 lines, and is very useful.

• With every shlok you recite, tie 1 knot randomly into your thread so as you finish reciting there will be 7 knots in total on the thread.
• Blow on the thread and visualise the energy of the Durga Saptashloki mantra entering the thread.
• Hold it in your cupped hand, focus on the Devi Chamunda for a bit.
• Your thread is ready. Tie this thread on your (or your loved one’s) right ankle or wrist or around the neck.
• Wrap it a few times on the wrist/ankle and fasten it using three knots.

I recommend the Durga Saptashloki because it carries the power of the entire Devi Mahatmya. It is also the easiest way to protect yourself. You invoke the Devi Chamunda in her fiercest aspect to protect you. In addition to wearing this thread, if you can recite the Saptashloki daily or at least on every Tuesday and Saturday, it will make your shield more powerful.

If you have faith on some other mantra to protect you, then you can use it. But be very clear on what mantra you are using. It should be in Sanskrit and from some standard reference book. However the procedure for charging and tying it remains the same. Recite the mantra in your mind and for every shlok tie a knot on your thread intending that its energy enters the thread and remains there as a knot.

This thread will need to be replaced in about 3 to 6 months depending on the intensity of the evil eye that might attack you. This is how to do it. First prepare a new thread as above and tie it on your wrist/ ankle/ neck. Then use scissors to cut off the old thread. Dispose the old thread in running water or under some green trees where generally no one will step on it.