Thi s is a basic piece of advice for players. It is designed to not only help you out, but also your GM, and make sure that there is as little confusion as possible. It's fairly straight forward: when you take a course of action, or declare an action, share what your desired result is as well.
I know, I know, that sounds like it should be obvious. Not the saying the result, but what the desired result is. Often times it is. If you try to steal a wallet, you probably want the wallet - or the contents therein. If you attack someone, you probably are looking to hurt or kill them. However, sometimes it is not that clear. Besides, even if it is clear, it still keeps things more straight forward for the GM.
As an example, in the Shadows of Esteren game I'm in the demorthien for our town has a pair of dire wolves that accompany her everywhere. One of the PCs made a point of hanging around with the wolves and being friendly with them. However, it wasn't until recently that he pointed out he was hoping to normalize the dire wolves presence in the town, and show people that they weren't frightening monsters. This wasn't something that the GM had accounted for, but was very important to what was going on in the game.
In other cases the path the player is on may not actually be possible, but the intended result can still happen and the GM can help them find that way. I've run a number of cases where a player had in their head that some part of the scenery controlled a gate or other thing to block off a passage. Rather than just let them attack the part of the scenery and fail, I directed their attack to what would actually accomplish their goal. It kept things going smoothly, and prevented the awkward situation where a miscommunication caused problems in the player's understanding.
It costs you nothing to share what your hoped for result is, and it can spare a ton of heart ache. If nothing else, it lets the GM know what you want to do, and if they know what you're trying to do they know what path to put you on to get there.