If BLW is something you are interested in, I would suggest reading the book to get a good idea of how to start. Essentially the theory is that you can give your baby anything from this point on, and if she has the skills to eat it she will. What you offer will depend on a lot of things - some fruits can be very slippery and hard to hold, and some raw vegetables are to hard to bite (but might happily be sucked on). Obviously you want to avoid choking sizes (size of a grape), and ideally offer large chunks or spears. LO needs to be able to hold onto it in her hand and get it to her mouth, so it needs to be long.
Gagging is normal, some babies take awhile to learn how to bite, chew, and swallow. The main points is that she is in control of what she eats, and it is more about the experience of learning to eat and not about how much food actually gets eaten.
There is a BLW support thread as well where you can ask more questions about the method.
http://babywhispererforums.com/index.php?topic=184657.0We started by giving DS2 any of the fruits or vegetables that we ate ourselves: pears, broccoli, carrots, melon. He had more success with some things than others. The BLW books suggests giving food in different states, so offer both raw and cooked. Things like raw carrots and apples however are tricky because choking sized pieces can be bitten off, but they can be cooked slightly to make them soft enough to eat. He didn't eat that much for many months, but it was ok and the whole time he was learning about food which was the most important part.