Real Time vs. Glossed Time
In general, when you role-play, you're going to be playing out each moment as it happens, describing scenery and playing the parts of surrounding people or creatures. This is called role-playing in real time.
But sometimes you're not going to want to play out each moment. For instance, if the characters are making a long journey on the road, or a character is spending a lot of time in training. At these times you might want to say, "the day passes without event, though you've traveled over some spectacular passes."
This is called role-playing in glossed time.
Role-playing in glossed time is enticing, because often the characters will be doing something that doesn't need to be played moment by moment. But it is dangerous, too, because it can be tempting to gloss over large amounts of time. This, however, isn't what role-playing is about, since playing in glossed time is lacking in interaction.
Thus, try to keep role-playing in glossed time to a minimum - save it for times when playing each moment would be tedious. And if you do use glossed time, remember these pointers --
First, never gloss over more than a part of a single day. It's alright for the majority of the day to pass uneventfully, but make sure that you play in real time during part of the day, and have something happen during that time, if only a conversation between characters.
Secondly, take the time to briefly describe what happens during glossed time. Instead of telling the characters that "you travel all day and nothing happens," say "you travel most of the day through woods that are broken here and there by streams. You have trouble crossing a couple of them, because the horses spook from the water and need quite a bit of enticing. But as the day wears on the streams become less, and when it's time to stop to camp, the land has risen into rocky highlands, and you hear coyotes or wolves crying out in the distance."
This gives the characters something to remember the day by, and you can also create a bit of tension with the addition of something like the howling wolves.