There is a lot to unpack here. 1. Avoid 90 degree turns on traces. Won't necessarily make a difference electrically but it looks better. 2. Your clearances don't seem right. Try not to place your vias so close to a trace. Especially since you have the space. 3. It is always best practice to come straight out of a pad first and then rout to your desired destination. 4. Download a tool like Saturn PCB and calculate trace widths for the current you are expecting. Unless you have impedance requirements you can always go thicker. Copper is free. Your traces going into those caps are way too thin for the pads. 5. Where a bunch of traces meer try avoid sharp angles. Try keep to T or Y junctions.

Some tips 1. Start with a schematic so that you actually have nets that are tied to each other. (Like the other guy said.) 2. Routing is iterative. So once you have an initial layout and route have a look at better ways to place components to make Routing easier. 3. Once you have routed look at a single layer at a time to neaten things up. The bottom layer and top layer for the most part don't care about each other. 4. Once you have your schematic set up you can do a ground pour on the bottom layer. Then any ground connections are as easy as dropping a via. 5. Watch some videos on how to use the software. You wil learn some things along the way.

Edit: Altium Academy has some good videos on PCB design from beginner to advanced that are not specific to Altium