Tips for a secure sew-in
Your hair needs to be very clean and dry prior to braiding.
Ensure that you wash your hair in its natural state and that it is dry before you start braiding.
Cornrows need to be firm but not too tight.
Tight cornrows will lead to breakage and even hair loss due to excessive tension.
Plan your leave-out carefully
Leave enough natural hair around the perimeter and parting areas to cover the wefts. This helps the extensions look natural and keeps the stitching hidden.
Use the right needle and thread
A curved weaving needle and strong weaving thread make it easier to sew along the braid without repeatedly pulling through the hair.

Sew the weft securely
Keep your stitches relatively even and close enough to prevent the weft from shifting. Avoid making extremely tight stitches that pull against the scalp.

Don't overload your foundation
Do not add too much weight to your hair if it is thin and delicate. Too much weight may strain your hair.

Feel the tension while you do that
Each time you do that, gently shake your head and hair. You will have to make an adjustment if there is any pulling sensation, throbbing, sensitivity, and a headache.

Tie off the ends correctly
Tie off each weft with several strong stitches and ties without tying up the same spot every time, thus forming an extra bulky look.

Be patient
The first installation needs time and patience. It is better to work slowly and accurately.

Most important: A sew-in should feel secure, not painful. If you're inexperienced, having a professional install the first one can help you learn proper braid patterns, tension, and placement—especially if your natural hair is thin, short, or fragile.