My birds are a little flighty, and with our having a small house I opt to clip until we buy a bigger place away from animals and an open concept kitchen/living room.
I look forward to having them fully flighted, but if you find yourself like me, worrying for your bird's safety (especially when they're new and don't know the house), here's some adivice.
When I clip them, I usually have my husband hold them and I hold out the wing and cut just below the line of the secondary feathers from the back. I usually clip 5-8 feathers, bird depending, so that they can glide but not drop and hurt themselves. They can still make it across the room if they're perched high enough, but never above hip height and below. Always cut from the body out, so if they move around they're less likely to get hurt, and try to cut in one smooth motion to keep everything even.
Also, I tend to leave the last two feathers intact. This is asteticly pleasing, and helped protect the interier feathers from damage. From what I can tell, it also helps with her gliding.
Here is my senegal in mid flap with my husband.
Hope this helps!