Hello EtherealSin, I wouldn't recommend summoning any entity unless you know how to banish them, summoning demons and not knowing how to banish them back can cause very negative effects on those who are around you and you, yourself. Demons have a habit of making host of those who summon them, meaning it will feed off your energy and anyone around you.
I agree, you should invoke angels in order to achieve your goals. They are much friendlier and they have the same aspects as demons as they are both daemons.
If youre asking those specific questions then I'd recommend you spend a lot more time researching before you do anything. Goetica and ceremonial magic is no joke.
How to summon?
If you have to ask this, you're not ready. Study more.
Any specific demons I should avoid?
Study. You'll find out.
Best way to find them?
Study. You'll get your answers.
Please help
Pick a system. Any system which seems interesting. Study it. It will have exercises which lead eventually to doing what you want. Until then, study.
In my opinion I suggest you don't summon the earls and mercury ones. Because to summon them you need to have a very strong mind and being active at the same time.
The dukes are fine to deal with.
Don't summon the kings because they need offerings but even if you manage to summon one without offerings your wish probably won't happen.
Lastly I would like to say when ever I tried to do ceremonial magick I always felt that they actually appeared way too sooner than they should be appearing. By appearing don't mistaken it for real appearance but rather the atmosphere the air changed and got heavier.
The air itself felt like the overwhelming power for me to handle. So obviously even before starting I closed the ceremony . And you know it really takes time for that kind of air to clear out!
But this experience cleared at least one thing and that is only just by making your intentions of summoning the one loud and clear will do the job. As if they are way too near you!
I hope this helps but remember in my case the overwhelming power that I felt gave me bad feeling so I stopped. The question at that time was will I be able to banish it if I started doing the procedure?
Basically, if you have to ask you are not ready to be working with them. Your time would be better served learning about magic and magical practices. When you are ready you will not have to ask how.
I agree with everyone when they say that if you need to ask you are not ready. But I do not agree with Lover4Ever when she says that you can just summon an angel because they are friendlier. Angels may have wings but they can bite too. Dont try to summon nothin at all if you can't even banish a lower enitiy. Scratch that dont try to summon anything until you are well educated on ceremonial magick.