Bracket your exposure for various effects. Meter different parts of the scene. If you have the time and patience, arrive at the location just before sunrise and make a series of exposures- you will get more dramatic colours and effects earlier in the event. For sunsets, also arrive early and hang in there 'till just before twilight. Picturesque cloud formations and skyscapes add to the effect. Look for compositionally effective landscapes and objects for foreground framing. You are shooting directly into the sun and at certain times, flare can be a problem- a tree or structure can be a handy lens shade from certain angles. Mist, steam, smoke, fog, airborne particles and pollution can add interesting texture and colours. Shoot a bunch and pick the best. Sometimes dramatic changes occur in just a few seconds or minutes. You don't want to see the best effect in your rearview mirror!

Additional edit- The colour temperature at sunrise and sunset is way below "daylight" midday temperatures. A daylight WB setting will usually yield a yell/red bias which is fine. If however, you also try some exposure at a "tungsten" setting you may get a cooler or more authentic colour rendition- may be surprisingly interesting.