Becoming a permanent resident is much easier than it used to be. The immigration bureau now has a points scheme that gives priority to certain professions, and it is publicly available on their web site.
For a person who does not benefit from the points scheme, Japanese citizenship is easier to get than the PR status. This is handled by the Law Offices (Houmukyoku), so please contact the office in your area for further details.
The shortest path for both is becoming a spouse of a Japanese citizen. Three years after marriage, you can apply.
Unless you have had problems with visa etc., both these can be applied for without the help of lawyers. An immigration lawyer will give you free advice once, but following up will cost quite a bit.