Ok, nearing the completion of my greatest achievement (my first HOF-er ever) in Life States Dynasties, I've come across several tips I wish I would've known at the start of my file.
On Marriage and Spouses:
>Your Sims don't have to love their spouses. I often will prep arranged marriages in the Sims, including a potent friendship elixir (or relationship boost from the Social Networking App that can adjust relationships) and a quick romance.
>Wait for your Sim to wish to be married to their chosen spouse. They will roll it eventually. I always arrange the spouse to move in as soon as my Sim becomes a young adult, so while my heir works on their skills they can be engaged and wait on the wish to roll. Sometimes absence does it, sometimes spamming romantic socials does it. Either way, be patient. It will happen.
>Remember that any spouse you move in can be changed. Plastic Surgery (as far as my knowledge goes) is completely allowed for them. So if there's simply only one vampire in town (haha, doubt it but roll with it for the situation) you can adjust them as you see fit. I often do this for Genies and Imaginary Friends as they have a tendency to be cursed with EA Pudding Face (all sliders exactly in the middle). The look was pretty... at first, until I saw that every other NPC had it too.
>In the beginning, try to make your first spouse count. Quinn was mine, he mastered several skills and set my Dynasty up for success. Xiri, my founder was only allowed to go at her handiness and inventing, while Quinn was unrestricted. He learned Alchemy and Logic and gardening along with several other key skills. So by the time I had my gardening Sim he had all the perfect fruits and veggies ready to be replant, my alchemy Sim had more than enough ingredients and I never needed to worry about having someone to tutor my heir/ess' through school or make young again potions until I had my logic Sim.
>You don't have to move early spouses out right away. I kept Quinn (as mentioned above) until my 5th generation became ready for children (so I could ensure multiples). By my 5th generation I had finally collected all the Sims who were capable of doing what he was (making young again potions and alchemy potions, running the garden and cooking).
On Requirements:
>Traits do not always mean your Sim should pursue a certain skill. If your Sim gets the Eccentric trait that does not mean they have to pursue Inventing and Handiness. It just gives them a boost towards that skill. Even Sims who Hate Art can still paint and be great painters. Try to coordinate skills less with traits and more with Supernatural Type. Leave longer-learning skills to longer-lived Sims (logic, writing, etc). Leave Fairies the gardening, cooking or fishing as that's naturally in their bones - even if they Hate the Outdoors. Leave the tedious skills you hate to Vampires who skill up faster at night. Have your werewolf pursue athletics and martial arts.
>Try to save your "dependent" skills for later on in your game if you can help it; things like Alchemy, Cooking, Inventing, Nectar Making and so on. I know you don't get to choose traits, but as said above - skills are not irrevocably linked to traits. Leaving these for later will give you time to perfect the ingredients/pieces that are a part of it. Things like collecting all of the metals/bugs/gems for your Alchemist or preparing those Pink Diamonds for your Inventor. Having perfect ingredients for your Cook and Nectar Maker can make all the difference sometimes.
>Always have a backup plan! Keep skills on the backburner just in case. I often will have all the toddlers learn logic and music (peg-box and xylophone) until one of those skills gets taken away then I switch over. Use those skills less as "getting ahead" and more for "just in case." My werewolf Sim would've had to learn fishing, but it was just long and tedious. He picked up some skill books for Social Networking and learned that super quick as he was already struggling with Collecting... which leads me to my next tip:
>Try not to lean on universal skills like Consignment and Collecting. I regret doing so in my file! It seems easy at the time to say "oh look, consignment skill challenge done, checkmark! Let's go make a baby!" (That was my reasoning, at least.) Try not to do that! It's so easy to forget that later on when you have a painter Sim that you can't just send them to the consignment store for fear of invalidating another's skill challenge.
In terms of housing:
>Keep it Simple. I made a house that was designed to be interchanged with every heir without changing the structure of it every time.
>Invest time in to making cells for your future generations. Generation 1 doesn't seem like a problem until you're on generation 4 and they just won't stop causing problems. I create basements and lock them in. I leave a ladder with the way out that's fenced off with a gate that's locked to everyone. I give them the TV from ITF (as it also has a gaming console included), a Food Synthesizer (so they have good food without learning the cooking skill - you could always include multiple fridges but only have your cooking Sim have the tools to cook with, you just run into the issue of Sims trying to prepare food even when they can't), a toilet and a sonic shower (the toilet is just in case they eat some bad food, all Sims have steel bladder), and a nice bed. I also put all of their skill-related objects in with them so they can keep themselves busy if the TV and gaming system simply isn't enough.
>Think about your computer's capabilities when building your house. If you notice lag in your games after a while of playing after a long span of time, try making the house more minimalist and utilitarian. Heck, my house didn't even have a walkway until about the 4th generation when I finally threw a fountain I got from one of the marriages down and slopped some pathway around it.
>Speaking of marriages and gifts, when you have a ton of money and no need to sell every last thing that is sent to you from other Sims, use it to decorate your house! It's free decorating! That painting/fountain/sculpture will help boost the mood of your Sim and thus boost the rate they gain skills!
On Misc. Items:
>On your first or second generation (preferably first) when money starts to become easier, go to a vacation location and buy up a dozen chests. Trust me, you'll want them, and here's why:
I noticed a long time ago my game would lag up on certain Sims. It started mainly with my Inventor (who was my founder). I was so frustrated that when I would be ordering her to do things that the game would lag horribly, but when I went to her husband things were completely fine. It's because of her inventory. Things can get bugged easily when there are a lot of them and cause lag. The scrap in her inventory was bugging her, so I put it in the Inventor's table and the lag went away. Buying a lot of chests (I prefer the look of them over alchemy storage, but those work too if you'd rather not travel) can help you sort your ingredients and other things and keep the inventories clean. I had a chest for fish, a chest for potions, a chest for Alchemy potions, a chest for alchemy ingredients, a chest for nectar making ingredients... you can be as organized as you like, or you can buy one and just store everything in there. Keeping inventories clean and as reduced as possible will help reduce lag.
Anyways, a lot of these have probably been said, but best of luck to all who are trying. This is such a fun challenge!
*Edit to add one more housing item I forgot.