The dominant image is of the 'tyger' as something powerful and terrifying; an unusual and unconventional metaphor for Christ. The speaker refers to the 'tyger' in the second person singular, as 'thy'.
There are several semantic fields, starting with light in 'burning', 'fire', 'bright' and 'stars'. Fear is covered by 'terrors', 'dread', 'fearful' and 'deadly'. The language of weapon-making appears in 'furnace', 'hammer' and 'anvil'. The effect is powerful and memorable