A while ago I decided to challenge myself to a nerd start without using Isabella and it's possible (without save scumming mind you) albeit somewhat hard and depending on luck.
As there is already a guide on doing max difficulty here are some more general tips:
Aura is key. Get your slaver to a good mood (bath, brothel, massage helps) if you can afford it buy the fashionable clothes and use the Magna Magnifica spell if your aura is not completely overpowering your slave.
The first 1-2 days you'll want to use the Sententia Veritas spell so you can apply heavy punishments for minor offences - humiliation category works best on Nerd/any character who isn't skilled at other types of punishment.
Set enough rules, but don't go too crazy. (humility and bath is enough early on)
At the end of the day, make sure you reward your slave to for the mood bonus (don't reward dates, they won't do much at the start)
Your first slaves on a hard character should always be maids or servants as they are easy and quick to train.
Dont hesitate to use Fairy Dust and Kamra to get more actions out of your day early on, once you've stabilized use it less frequently on your slaver to avoid addiction.
On Nerd difficulty, before you even start training a slave, spend a few weeks in the slums, only go to arena and do sparring, it increases your action points, fighting skill and arguably most important, your aura.
Some comments on this with the upcoming 2.2 release in mind:
1. You'll be able to watch the races/arena battles without participating for a boost in mood.
2. If your slave is not willing to relieve your libido, visiting a brothel can help.
3. On normal obedience difficulty, 2 rules is enough, but on hard you need at least 3 to avoid spoiling. "Force rules" counts for this purpose. Force humility is one of the few rules that can be forced without needing to buy an item (force silence, for example, requires a gag). Deny masturbation, deny orgasm and act as maid are rules that usually won't be resisted early on, even without "force rules" ... but be sure to disable deny orgasm before using the Delikacia spell unless you want the slave to feel guilty. (At high enough obedience levels, in 2.2, it will be possible for the slave to resist orgasm with Delikacia and instead raise their arousal).
4. You will be able to buy faerie pollen and kamra without having a laboratory, e.g. while still living in the Slums.
5. Instead of waiting to obtain a slave and sparring alone, you can buy a cheap, low-stamina slave and have them do gymnastics (in the slave activities menu), which trains stamina without using the master's energy, so you can spend your time sparring while she builds up her stamina, and over that time period she will also make some progress on other aura stats. For this, it is also helpful to put a collar on her, which is anyway a good idea together with a brand to prevent escapes.
6. Fairly obvious but if you need to take a loan to avoid bankruptcy, it's best to wait until you are almost out of sparks, to maximize your time before having to repay it.
7. If you are living in the Slums, you don't have a kitchen so you can't train Cooking at home, but sending a slave to the academy with rubber gloves, a hijab and an apron or academy uniform can raise the skill quickly if the slave is diligent.
