Basic noob qestions.

[Niwashi]

The answer to all three of these questions is right there in the quest objective. If it tells you that you have to be dressed in a weathered shepherd's tunic and a pair of weathered shepherd's slops for the next step, then try putting on the weathered shepherd's tunic and weathered shepherd's slops you were just given for that purpose. If it tells you you need to complete a leve quest, then do that leve first. If it tells you to deliver a bottle of orange juice, then you need a bottle of orange juice.

When quests are red and locked to you, that means that you do not fulfill some requirement for that quest. Could be that you are the wrong class, or too low level, or don't have a required item, or haven't done some required action.
Try picking it up, and it should say what requirement is missing.

It will always tell you what requirement(s) you're missing if it's a new quest you're trying to pick up which is locked. If, as in these cases, it's an ongoing quest that you're trying to advance, then it may or may not be that direct, but talking to the NPC will generally at least give you an extra clue about how to proceed

For instance, if you talk to Swyrgeim when on the "deliver a bottle of orange juice" objective of Color Your World, she'll point out that the merchant right there in Vesper Bay sells it. The game doesn't actually care whether that's where you get it from or not (which is why there isn't an intermediate objective/destination there). There's several merchants who sell it, or if you're a culinarian you could make it yourself. But she points out the quickest and easiest source.