Angel or Demon Summoning/Creation (Method One)

To begin, recognize what you are doing. You are not just creating something to exist, but are creating a partner to work alongside and befriend. This being is similar to a tulpa but different all the same. You can choose to perform the below method or create it in a method similar to tulpamancy.

Nextly, you need to decide what you want this being to appear as. Their hair colour, their height, their eye colour, their facial shape, etc. Then, choose for them a name. This name will be very important, as all names are. If you so desire, you can give it a "mortal" name and a regular name. You would keep the regular name secret. 

If you so desire, you can make a hybrid. However, this will require more focus and energy on your part. Although I am sure you can do it if you so try.

Afterwards, you can choose a sigil, item, or the like to represent the being. No matter what you choose, you will, of course, need to assure it is unique for the Demon/Angel you choose.

Afterwards, picture the item in your head, Put energy into the item you are envisioning, then send the information into it as well.

The rest of the creation depends on how you prefer it to be, so go with what is natural to you. If you like a spell for it, I have one prepared:

Say once while picturing the item associated with the being, "Bring to me that which I created. Make (him/her/them) be more than a thought. They shall help me and I shall help them. This is my request, so mote it be."

The estimated wait time is a week to two weeks, or more if you wish to form it over time instead. Keep in mind, however, the being will not be physical.  It will merely be for you and will be able to communicate with only you (mostly.) As stated previously, it is similar to tulpa creation. 

Good luck with this, and blessed be you and your partner!