The fickle world of fashion can be incredibly frustrating when trying to figure what's in, fashionably speaking. Fashionistas constantly seek the newest, hippest, most in item as quickly as possible, so you may feel like you are in a race to stay on top of the game. If you are wondering what's in for a spring, summer and fall, look no further than the fashion magazines that flood the newsstand. Regardless if you are a devoted subscriber or possess a passing fancy in fashion, use these great sources to determine what items are considered the hottest for the upcoming season. Also, take a look at stores and the streets to see what people are buying and what they are wearing. Although the world of fashion may take a drastic turn at any minute, this year's must have items are the following: Jackets, jackets, jackets to adore The preppy look is back and jackets, blazers, and coats are now more popular…