Most succulents are more sensitive to over-watering than under-watering (Echeverias are a great example of this). The easiest way to tell what a plant’s water needs are is to look at its leaves. The thicker the leaves, the less water they need.
While it’s generally a good idea to combine succulents with similar water needs, if you are using the “soak and dry method” with a well draining soil in a pot with a drainage hole… you should be fine to combine just about anything.
You may find it helps to pour water directly around one or two succulents that need more water than others from time to time, rather than soaking the soil for the entire pot.
Light is also a consideration you’ll need to take when pairing succulents together. Some plants, like Echeveria imbricata can handle full sun with afternoon shade, but Haworthia fasciata prefers light to partial shade.
The best way to know how to water is to start by knowing which plants you have. Once you know what plants you are working with, you can determine their watering and light needs.
Again, if your soil is well-draining, and you are watering correctly, you should be able to pair most succulents together and keep them happy!