when I am doing a panel from scratch, what I will do is strip all outer insulation back to the connector, from there I start with usually the top of the panel ( or sides, or whatever depending how the wires enter the panel and how its mounted ) anyway I group all the grounds together and tie them in, then do the same with the other side or bottom, then repeat the process for the neutrals, and finally the hots, but also group them and leave them long enough to go anywhere, but bundle for circuits 1,3,5,7 ect. then repeat the even side, so when its done, all the grounds are at the back of the panel, neutrals in front of them, and hots up front.
hope i did not confuse anyone with that explination, but its what i do and makes the panel neat and easy on the eye, and usually the inspector looks see's that and smiles and leaves.