I was reading some tutorials to create new library from the existing library part1) Making new devices is something you will need to do sooner or later. Sooner is better. Usually, you can find a suitable package. There is one for that chip in the Eagle library. Then all you need is a symbol and there are probably other 44-pin devices with the same pinout. If not, get something close and modify it. Then connect the pins to give your own device. Set up a personal library for those devices rather than add to an existing library. That library will grow.
1. In the EAGLE control panel > File > New > Library
2. I see options new device/footprint/3Dpackage/Symbol.
3. Clicked on button new devices
4. In the dialog that pops up click import...
5. import this PIC16F874L
see the screenshot
It would be to early for me to mix all the part's. I am following rule one step at one time. so first priority is some simple circuit2) Your current design does not include connections for ICSP. You probably want to add them.
3) It is better to start with an actual schematic. Then you will have electronic rules check (ERC) and schematic capture for the PCB design that will help find errors.