You blood is your life essence, so be very careful with it. It will always link back to you. I'd advise against using it to curse or bind. And it can be necessary in blood oaths or in blood devotions to some deities.
Please be very careful using blood in spiritual workings. Always use sterilized equipment and common sense.
Blood is Life,The Aincents saw blood as a way to bridge the Gap between world's and give entities a life line while visiting us
Its said curses or pacts made using blood are forevere..
I sometimes add a few drops to poppet spells or floor washes
A few drops of your own is all that is needed
As the others said be careful and if you are new to spell craft its better starting with lesser magicks