I'll identify the parts of speech for you. That will help you to diagram the sentences yourself.
Both(adj.) the(adj.) girl(n.) and(conj.) the(adj.) horse(n.) looked(v.) at(prep.) each other(indef. adj.) in(prep.) fear(n.) and(conj.) anger(n.).
- girl and horse are a compound subject
- at each other is a prepositional phrase used as an adverb to modify the verb looked
- in fear and anger is a prepositional phrase used as an adverb to modify the verb looked
Start your diagram like this: girl (and) horse| looked
Remember to place your adjectives and adverbs on slanted lines under the words they modify.
Now, try to do the second sentence by yourself.
Visit the sites linked in the sources section for more information and tips on diagramming.