Reddit reviews Writing Systems of the World

I agree with /u/_Hunyadi that orthographies tend to evolve as they're written more (simplified characters, or finding characters too similar and modifying them).

For the type of paper, I think this would depend on what you're trying to accomplish and what type of writing system you're trying to develop. For a rough draft, blank might be fine - but if you'll be writing your language mostly with lined paper, take that into consideration on how characters will interact with the lines. Blank paper is good for the initial run to just draw out shapes, though. Once you have some ideas, then maybe switch to lined paper.

I highly recommend taking a look through some books or websites about different writing systems. I have this book. It's not a very detailed book, but does serve as a very brief overview if you're not familiar with different writing systems. Wikipedia is also a good source, with quite a bit more information.