Sit down! take a seat, pull out your good old notebook or A4 American paper, a ruler with sharp edges and number 2 pencil and an eraser.
Start drawing out, what you think, looks good. Get inspiration from the product you really like, learn there flow and design and incorporate that into your sketch.
You are stuck on Inspiration go to Dribbble, we what other UX/UI designers are doing. all you have to do is search you will find amazing people better then you creating amazing designs. No need to recreate the wheel learn from them and incorporate that into a sketch.
Once you have to design on paper.
Download this amazing app called Sketch, yes there is a learning curve but that is with anything. The last I checked this app is only available for MAC. PC users you can always use Adobe Photoshop.
once you have your designs ready.
There is Invision app and Marvell App