After wasting an whole month (the sixth) persuading DS to be spoon-fed puree, we offered him finger foods instead from the seventh month on, and since then have never looked back. Now DS basically eats 2 meals (breakfast, lunch) and 1 snack (late afternoon) together with one or both of us everyday.
What? We started with sweet potato, broccoli, potato, banana, avocado. But during 4 months of practice, we have already offered DS virtually everything: (except potential allergens, and we monitor the sugar and salt level very carefully): greens, apple, "p" fruits, chicken, fish, dry cereal, ricecake, rice, (homemade) bread, tofu, all kinds of melons, egg yolk, macaroni, spaghetti, baby corn, baby carrots,..., etc. We make sure that we offer DS a great variety of food which together provide balanced nutrients like carbohydrates, proteins, good fats, (soluble) fibre, and vitamin C (from fruits and vegetables) and minerals like iron (from fish, chicken and egg yolk in our case).
(DS is still being breastfed 6~7 times per day - so actually we are not worried about nutrients - we just want to build a good foundation before DS is older.)
How much? To prevent premature weaning from breastmilk we only offer solid after DS is nursed (we try to wait 20 minutes to prevent interference with iron absorption, but somtimes we can't). When DS is full he will let us know he's enough. Actually he does not eat much solid (but sometimes he surprises us a lot!), maybe just several bites (or occassionally none) of every type of food we offer: we know that at this stage our aim is to let DS explore the world of food and develop his mouth and hand skills, not to concern with the amount of food he actually swallows.
What size to prevent choking? To the contrary, we think bite-sizes are not safe for the beginner solid eater - we are worried a bite size piece can go through the mouth too quickly. At first we always give DS a food piece cut in chip, stick or finger size that he can hold it with his little fist. Then he can suck the portion going out of his fist.
To ensure safety, we always make sure that DS sits upright, and resist the temptation to put food directly into DS mouth. Even when we must use a preloaded spoon (e.g. with very runny food like porridge), we let DS grasp and put it into his mouth himself (while we hold the spoon handle in position) - we hope to give the control back to DS to feed himself.
At the beginning we only offered food pieces after we had tested: those we ourselves can eat by mashing in our mouths with our tongues (without using our teeth), to make sure that the texture is soft enough for DS to chew and swallow. We concern this much less now, not only because DS has learnt how to use his teeth to gnaw (e.g. as in the everyday apple - his top favourite), but also his gums have become very strong.
DS has never choked but still occassionally gags (though it becomes much less frequent now), because sometimes he doens't know how to "process" the texture of the food (esp. fruit skins), and we know the gagging protects him from choking, so we are not worried (actually DW is more scare and sometimes needs my resurrance ;-P). I remember the first time when DS ate plum, he gagged a lot and spitted the flesh out with a lot of saliva (I don't know where the huge amount came from)! But after one month of "practice" the plum was already one of his favourites. So, gagging is a valuable lesson for DS to learn eating food safely.
If you are really fearful of choking, I suggest you to have some knowledge of baby first-aid, then you will be less frightened and more relaxed (you should know the difference between real choking and mere gagging). But anyway if you observe the principles of baby led weaning stated above (e.g. baby sitting upright, never put food directly into baby's mouth, avoid hard round small food like peanuts, grapes, etc.) this should be very safe. No need to be panic.