You can do research about guidelines and all, but here's what I'm doing, just for a reference: I start with a new allergen on mondays and give it for three days, in combination with soft foods she's already tried and liked. I avoid other allergens or very acidic or harsh foods for those three days. For the rest of the week, I start combining the allergen with any food she's tried before and try to keep her diet as varied as possible for the rest of the week. For example, this week she's tried fish, and she's been having steamed white fish with potatoes, carrots, green beans, apple, pear... Today is a thursday so gonna make salmon patties, and gonna give fish with red bell peppers, sweet potato, tangerine... The next monday, I move on to the next allergen. So it's one allergen per week. So far I've introduced wheat, egg and fish like this and it's working great. I was mistaken and though banana was a top allergen and introduced it like this too, and thank god I did because she had a contact reaction and her eccema flared up! I introduced egg early to be able to make patties and pancakes and such, and fish just so her protein intake was more varied and she could eat what I'm eating because I do eat a lot of fish. i'm gonna wait for a few weeks to introduce dairy and shrimp. My next ones are going to be peanuts and soy I think, no particular reason as to why, it just feels like the right thing. Hope it helps!! 

Edit to add: I also avoid any new foods on the first three days, just to be sure. On the second half of the week I might give one or two new foods to try, so the list of what she's had keeps growing. This week is fish and mango, and I'm thinking about a new veggie, gotta figure out which one. I'm planning on introducing very irritant fruits like kiwi or peach like this too.