Read through the theory of sutures. This will give you a good grounding on classification of suture types, sizing, and their respective removal times based on anatomy. 

Familiarise yourself with the instruments used for suturing, their names, and how to utilise them proficiently. 

Watch the video's explaining the various suturing techniques. Slow them down, pause them, and rewach until they are second nature.

Utilise your clinical skills resource centre, practise makes perfect. 

Be bold. On your surgical placements ask to assist in closing up that last layer (under supervision of course). There is nothing like real skin.