With all the other great advice here, I'll add:
Take the time to actively think about your story/characters.
In the car drive, in the shower, when you're washing the dishes, when you're waiting for the microwave / kettle to finish heating up and you've got a couple moments to walk around your place actively miming and talking as said characters. Take the time to be your characters, how they would react to your world.
You don't have to deep dive, but the decisions you make then, and the reworking of dialogue aloud will save you time when you're writing.
In terms of physically writing, just write. No, but like really. Just put it down and move on. You've got a great sequence and you don't know how to bridge it --(CHARACTER SAYS SOMETHING WITTY AND PUNCHES THE JERKFACE WHO INSULTED HIM)--and then you continue onward. Write down your ideas to yourself without the fluff.
Then character asks for a milkshake, but is taken aback b/c aliens attack. (Aliens look like lizards who smeared avocados on their skin, took a bunch of acid, and think they're going to Cochella) Character's 'spidey-sense' activates and they magical girl transforms into HERO. They kick-ass like a powerpuff girls sequence. At the end of it battle, they go and grab their milkshake covered in guts. they wink and say something dumb-witty about a new facial treatment from the spa.
I keep a thesaurus open / handy, and there's other great websites that help with word finding, too. Also, a pinterest board of writing references, even if it's just emotive words.
*will post, let me know.