Sleep is such a challenge. It is both developmental and learned, which makes it especially challenging to figure out when your child is developmentally ready to learn. Because, as we know with everything else, there are normal age ranges, but all children develop at their own rate.
I am with those that say that BabyWise may work for some babies, but probably isn't the best idea for most. Healthy Sleep Habits, Happy Child worked well for me. There is a lot in there. There will likely be some crying, but one of the points it makes is that if you put your baby down at the right time - when she is tired but not over-tired, there won't be much crying. I find that to be true... but it takes a LOT of focused attention to read you baby's cues that well, however the guideline of two hours from the last waking point in the morning is a pretty good one... sounds like you might be putting your daughter down to soon if she's waking at 8 AM.
The same book says that there are short nappers and long nappers and nothing will make a short napper a long napper. My older daughter took 3 45 minute naps until she was much older (around 10 months or so). My younger daughter, who is coincidentally 6 months old, took longer, hour and 1/2 naps starting around 4 to 5 months. Recently they became short - around 1/2 hour again, and I noticed today she is cutting a tooth. I now expect that's the culprit, and we'll soon have longer naps again - until the next tooth.
To be honest, in my experience, with the developmental changes to sleep, and the addition of teeth and the occasional cold, the only thing you can count on is that things will only be predictable for a few weeks at a time at most and then something will change.
I don't think I could have worked from home with my older daughter. Some ages are better than others certainly, but things are always changing, so it's hard to count on anything. If you really need to make it work, you'll need to get creative, because nap times alone aren't likely to work. I would suggest getting a sitter to come in for some time, and also a baby carrier - the ergo will let them hang out on your back and in front, and on your hip, so you can work and hold her. And toys, toys, toys - an activity center, maybe sitting her up in her boppy near you on the floor with toys.
Good Luck!
A.