Road Signs
In the opening of the film we see Lawrence passing road signs warning him of danger due to road construction. They are a symbol for the man as he begins to travel faster and faster on his motorcycle. The foreshadow his coming crash to avoid bicyclists on the road ahead.
Putting the Water Back
We see Lawrence put his cup of water back into his canteen after Tafas tells him that he isn't drinking at this marker. The symbol is that Lawrence does not desire to be different than the people he is serving so, by putting his share of water back into the canteen he is showing Tafas that he desires to be united with him in the journey.
I'm Different
While resting for the night we see Lawrence and Tafas speaking before sleep. We learn that Lawrence is different than the other people he is serving and Lean cuts to a shot of stars on one side of the screen with the moon on the other side, no stars with it. The symbol is that all the stars represent other people who are attempting to do what Lawrence is doing and the moon is Lawrence. The stars burn on their own fuel and for their own sake and literally have already burned out by the time we see them on the earth. The moon, though has always been with the earth and reflects the light of the sun which is the greatest source of light in the galaxy. Thus the image shows a great symbol for who Lawrence desires to be to the Arab people.
Railway in the Desert
Just before crossing into the last portion of their journey through the desert we see Lawrence, Sherif and all of the men before a railroad line with telephone wires attached to poles. The symbol is that modern society is cutting through the ancient desert. Just like England is attempting to bring the modern world to the Arab war.
Burnt Offering
After Lawrence returns with the man who lost his camel in the desert we see Sherif burns Lawrences English military clothes and give him traditional garments from his tribe. The symbol is that Lawrence is no longer an Englishman, but a man of their tribe. He is accepted as one of them and not considered an outsider by Sherif and therefore by his men.