When it comes to saints...well, sorry, being Catholic I get free access. Direct line. No call waiting. Comes with the territory.
I just ask. Nothing fancy. My favorite saint is St. Anne, patron of lost causes. That's me in a scallop shell, and she has this attitude, as in "when all else fails, try and resort to consensus reality". Works like a charm, which is why she would consider it a miracle if I went there of my own volition, being pretty much allergic to it. Thing about saints...they have heard it all and then some. Whether you say a novena, stand on your head, refrain from eating chicken for a month or light candles, that is all on you. I just talk to them in the same way I would talk to my car if it decided to stop working. After all, they are all around us, all of the time. They are not a celestial tax audit. They don't carry lightning in their teeth. They are a communion, and all of the metaphysical niceties of heaven above and earth below need not apply. You don't have to be a saint to call one either. If you want to go traditional, say their name three times. Some have hearing problems. In short and sweet, they are about as close to embodied as you can get without having a body to go with it. If you don't believe me go somewhere where peeps be like "Tony dear, find my feckin keys already." But I say that from within a lived-in tradition. So...
I draw the line with Expedite and other folk saints. Expedite tends to cross liminal borders with impunity, and I would not want him to expedite me to where I'm going soon enough anyway. I would offer him prayers and candles and such in accordance with his ties to certain magickal traditions, and the nature of the work within those traditions that pertain to him specifically. Same goes for Santisima Muerte, because context does matter. I was not born of the tradition, culturally or spiritually within which she arose. And if I were down in Santo Domingo I would make sure I knew exactly which Saint Anne I was praying to, partly out of respect for a tradition that I don't belong to and partly because it is just good psychic hygiene. In other words, I meet the saints and spirits of any tradition on their terms and according to the protocol prescribed by the tradition within which they are honored. I don't collapse my tradition into someone else's. I don't appropriate. I don't syncretize, I don't pretend to belong where I do not. I approach them as I would were I a guest in their house, which I am. In other words, stay in your lane. Work with them from within your own cosmology, your own beliefs. With the saints, need is what matters. So is sincerity.