I guess its somewhat straightforward to look 'natural' (or at least unintentional) but it would not be pleasant at all. If you live somewhere with cold winter months and nearby enough to a large wooded/forest area it is easy enough to tell family that you are going solo camping or hiking, and then just get purposefully lost and starve or freeze to death. Similarly you could technically go somewhere high like a mountain and fall off, but inconsistent terrain and availability based on the landscape where you live makes it a toss-up.
It's also worth noting that any suspicion beforehand would affect it. Ex. do you have any formal diagnoses, or a history of mental illness, etc. And afterwards if any evidence is left (like an account here), there is chance it is found and ruins any possibility
It is very hard to conceal most procedures. Any chemical methods are almost guaranteed to be detected in autopsy and others like hanging cannot be assumed accidental. I would say that the vast majority of suicides are found out to be such. I don't really have any meaningful advice I can give, apologies.
