For me its about planning, going slow and playing to the strengths of the particular knife I'm using. For example, weight wise I can decide between an Izula, or a Vic Rucksack. Sure the rucksack blade isn't as robust, but the saw takes up the slack and even in small stuff, notch and break it safer, and faster than cut and break with blade. That being said, I know I can lever, baton, or otherwise abuse the izula, so if that is what I had, I wouldn't be so gentle, and just get the job done. Something with a better handle, then its even faster, but I hit an effective limit where I don't gain much as the blade gets longer, at least until it hits chopper size. so that whole 4-10 or so inch range is kinda not great for me.
A blade shape that allows you to choke up and use different palm or blade pinch grips can allow you to get more leverage on a small blade. I've found I prefer "taller" belly knives than "short" ones for this. I don't know how much grind makes a difference, but I feel that smaller knives don't benefit from being thick and chunky. I feel like thin and slicey takes advantage of the size better, since precision can be used to greater effect.
I agree with Inazone that hand size makes a big difference too. I know a lot of guys really didn't like the size of the RC-3 when they were re-released, but for me the handle size is about perfect, and so the balance really works. in a case of small hands making things look big, balance wise a mora2k feels long to me. At one point I carried a SOG Seal-team elite. great knife, but for me there was only about 0.5 inches of effective flat blade once I reached past the serrations. That started me on my small knife road. And now that I live and work in a place where folders are more expensive and more tightly regulated, I'm glad I've got some small, fixed, folder stand ins that work really well.