Traits of a Successful Tulpaforcer
In my opinion, any two of the following:
Determination is how bad you want something. It's derived from the reason you decide to create a Tulpa. If you decide to create a Tulpa on a whim without much forethought, perhaps your determination may falter. This doesn't always hold true though, as I've met some very determined people who had no breathtaking reason to create a Tulpa. Without determination though, your Tulpa may not become as well formed as if you had a certain purpose and drive. It might also prompt thoughts of giving up, which is something you just don't do with another living being.
This is your stick-to-it-ness, your ability to continue forcing through the thick and thin. There will be downfalls. There will be low points in this lifelong journey you're embarking on. Forcing a Tulpa takes a lot of time: your whole life. Will you be able to see the light on the other side of the tunnel? Will you be able to keep calm and force on? Your Tulpa is a person, will you be patient with them when they're learning to vocalize and possess? Forcing isn't difficult, it just takes patience.
Being in touch with the internal workings of your mind is perhaps the most important skill you can have. Tulpaforcing will surely blow your mind. You will experience things you never thought possible. You will question many things you thought were facts of life. Being able to remain calm, cool, frosty even, during these trials will allow you to progress smoothly and enjoy the process.
The following traits are nice but not as imperative:
Being capable of loving your Tulpa.
I've heard of some strange host-Tulpa relationships, but all the healthy ones love and care for each other. Even people who's Tulpas are rambunctious macho types care for their host in subtle ways, and their hosts care for their Tulpas. The types of love that can be shown to Tulpas cover the whole spectrum, just make sure it's pure and selfless (as all love should be).
Being capable of loving yourself.
This is perhaps more important than being able to love your Tulpa since they share the same brain as you do. The number one commonality I've seen in people who make slow progress at Tulpaforcing is they put themselves down or are very negative. If you have depression (I think most of us do) I advise seeing a counselor or talking to someone who can help. Tulpas can help you with your self-esteem or with depression, but they are not just psychology robots. They're living beings who will occasionally have their own troubles, which you will need to help them through.
Of course the ability to put yourself in one's shoes is one of the most important abilities anyone can have. It enables you to feel and picture what life is like for those around you. Even if you don't tulpaforce, you should practice this and make the world a better place!
I now understand why monks used to do this: because it takes sheer mindpower, causes you to rethink your mindset, and improves your life in the long run. If you don't already have some of the traits listed above, please don't start Tulpaforcing. Your tulpa will not magically help you gain them, though they can eventually help. Instead you should look into developing yourself as a person. Improve yourself so you can be a better host for your tulpa.
If you do have some of the traits above, or are working on cultivating them, please do the following:
Think long and hard about whether a lifelong Tulpa friend is right for you.
If yes, realize that tulpaforcing is easier than some people may make it out to be.
Stay calm and force on :)