I'm a self-taught sewer, and my advice is youtube it up! lol Youtube is SO helpful because you get to see what they're doing rather than just read about it and get confused. lol If you want more instruction you could also look into sewing classes in your area, or just ask a friend for help.
Also, a very important step in sewing is finishing edges so the fabric does not fray. That will make it look more professional and make it last longer.
I'm just learning how to make props, so I'll let someone else answer about the sword XD Those cosplay choices are pretty awesome! I hope I get to see them when they're finished