Glen Scrivner has posted on three approaches to Christ in the Old Testament. He suggests:
1) From the OT forwards Basically you point out where the OT reveals an Appearing LORD, the Angel of the LORD, the Commander of the LORD’s army etc. And you say ‘Look – there He is.’
2) From the NT backwards Basically you show how Jesus and the Apostles just assumed that the OT saints knew Christ.
3) Systematically Here you point out how Christ is the Image, Word, Way, Truth and Life of God – and always has been.
Read Glen's entire post here.