I decided to post my own method of making spaghetti straps.
Step 1 : Use a blunt needle and a thick thread
Step 2 : Fold a 4cm X Whatever length you want , fold into half and sew it around 1cm width
Step 3 Tie a big knot at the end of the thread and pierce it thru a single layer of the fabric cord
Step 4 Insert the needle like this. The head of the needle go into the cord first
Step 5 Pull it until and take out your needle
Step 6 Continue pulling everything out. You need to use a bit of strength for this
Step 7 TA DA !!!.. Here is your fabric cord, cut whatever length you want and sew it on your t-shirt.