In January 2019 the Director of the USPTO issued new guidance to the examining corps that caused them to be much less strict on giving 101 rejections. The 3620, 3680, and 3690 art units, which examine business methods, are still very strict due to the nature of the subject matter (Alice was about a business method).
Many patent applicants were happy with the changes to examination. Some, like I, are concerned that examiners will now allow patents that courts would find invalid under 101. To ensure that your eventual granted patent will be enforceable, it is important to understand how the courts apply 101 law.
In opinions of the Court of Appeals for the Federal Circuit (the top appeals court for most patent cases), an often repeated word is "specificity". Also, "results-oriented" claiming is not sufficient. My summary is, "don't just say what it does, say how it works".
Specificity does not require that the claim is long, and many long claims have been found ineligible under 101. Furthermore, machine claims are not significantly more eligible than method claims. Only 2 cases that I can find have been decided on 101 grounds based on claims in means-plus-function form. One eligible, one ineligible.
I maintain a growing document listing almost all claims analyzed by the Federal Circuit on 101 grounds since Alice and excerpts of the court's explanations for why they are or are not eligible. Though you might use some eligible claims as a template for your own drafting, I think that the document is mostly useful for study.
You can download my document here and a similar document for European Patent Office Board of Appeals cases on subject matter eligibility here.
Multiple resources are available here. The "October 2019 update" is a fairly small update to the January 2019 guidance. That is available here.