Part of the fun of cosplaying is the quest for the perfect costume. And I'm not about to take that enjoyable experience away from you which is why I don't recommend you to come to me for a full costume commission. There are ready-made apparel that you can just alter and there are gazillions of patterns you can use if you want to make your own. To you die-hard DIYers out there--my hats off to you ^_^ And to those of you who've always wanted to give it a go, here are helpful and time-saving shortcuts:

On Patterns
You already know that patterns are great. But if you can't find a pattern, try to find a piece of clothing that closely resembles what you want to make. It might be hiding in your granny's drawers ^_^ say, a dress like Robin Sena's. You could also hunt in second hand stores as well as garage sales. Now carefully rip the seams and you're on your way to making a custom pattern. You can use newspapers for big projects or brown craft paper if you are working with lighter-colored fabrics (so you don't get them dirty with newspaper ink stains)

I know that most commercial patterns have the seam allowances already figured in but for a beginner, approximating the seam allowance while sewing could be a daunting task. Here's a trick I've learned from girls' school, so good I use it up to now: CUT YOUR PATTERNS TO SIZE. When you lay them out on your fabric, trace the patterns as is and voila--you have an instant guide! Your chalk or washable marker line is your sewing line. Cut the pieces with the necessary seam allowance that you will be comfortable with.

I use cardboard for frequently used patterns (it makes sense, but you know that already) but if you're working with a slippery material like satin, try using sandpaper with superfine grit. Your patterns will stay put on the fabric and you can cut with increased precision.

On Fabrics
Fabric shopping could be an enjoyable task. I don't recommend just going to a single store and buying everything you need in one shot. If you have time, visit several fabric stores and don't be afraid to ask the store attendants about fabrics that would befit your project. Go up and down the aisles to familiarize yourself with different kinds of fabric. Feel them, swing them around, test how they drape and don't forget to look on the bolt ends for washing instructions.

Make a note of the fabrics you want (according to your budget). And when you're ready, add this to your shopping list: several yards of cheap muslin. Costume fabric is expensive and if you're really on a budget, you only have one shot at making your masterpiece. Here's where the muslin comes in. Practice makes perfect--so do your project on muslin first and see how it will look.

I always do research before embarking on a project and thank God for the Internet it's easier than ever to find help. There are a many sites that offer tutorials and hints & tips. Here are a few that I've found helpful myself:

• Polar Fleece Facts

I won't post my own tutorial because I have very limited space on this server. And since other people have done it before, it'll be redundant for me to have another anyway so allow me just point you in the right direction:

• MEASURE YOUR HEAD first! Stark & Legum shows you how to do it right.
• marthastewart.com has instructions for making simple yet great looking hats
• m o u s e h a t : d i y has a photo tutorial for a 4-panel mouse hat
• COSPLUS has an illustrated tutorial for a Dejiko Digi Charat kitty hat

Alternatively, you can follow these simple instructions for a 6-panel hat. It takes more time but you will be rewarded with a custom fitted hat:

• Download the free program Wild Things! from wildginger.com
• Install and run the program.
• Choose the baseball hat pattern and input your size.
• You are now ready to print. Remember that you only need one of the 6-panel triangles so be sure to choose the page you will print so you save paper.
• I add a hat band as this reinforces the base. I cut it at 4" wide and 1" shorter than my head circumference to account for the stretch. If you want a hat band that you can pull down to cover your ears, double the width.
• Add whatever animal ears you fancy or a pompom on top.

• Unless your hat has wires (handwash in this case so your wires don't get misshapen), fleece is machine washable in gentle cycle. Unfortunately I couldn't say the same for felt. Which is why I quit using it as appliques for my hats. I want it just like my shirts--wash n' wear.
• Use POWDERED detergent and no matter how tempted you get, do not use liquid detergent or liquid fabric softener on fleece. They don't make the material any softer.
• DO NOT iron. If you really have to (like making a crease or fusing interfacing) use a light cotton fabric between the fleece and the iron (an old shirt will do).

• Anti-pill Fleece - my most widely used material. Very inexpensive and easy to find in a variety of colors. NOT to be CONFUSED with the other often-on-sale-at-Joann's Alpine fleece--this does not have a non-pill finish.
• Micro Fleece - my material of choice. Lighter and looks more sophisticated than it's "country" cousin. 
• Stretch Velour - Available in a variety of shades and shine. My personal favorite are the ones that have a matte surface (the shiny ones are kinda tacky). These are as light as micro fleece and often cheaper.
• Suede Cloth - In place of felt appliques, I've come to love this. It is thin enough to not add bulk to your detail and they don't fray.
• Micro Suede - Luxury! The look and feel of suede in a fabric (a plus for vegans)
• Micro plush - Often used in quality stuffed toys/plushies, one touch and you'll be sold (that's how I came to love this). We asked the saleslady if it ever goes on sale. She said "no, all people have to do is touch it, and we sell a lot of it".
• Crushed Panne - shiny, crushed velvet-like, very stretchy and relatively inexpensive in a variety of colors. Sometimes used in cheap stuffed toys (and I mean cheap--like carnival cheap)
• Alpine fleece - When I can't find a color match in anti-pill fleece, I will resort to this one. Just a little better than felt. Available in a variety of colors and as I said often on sale at Jo-ann (all time low of $2.99? per yard)
• Felt - Always readily available in a variety of colors. I use this when I don't intend to wash the project.