Keep transferred amounts small so as not to arouse law enforcement interest (less than $500 per transaction). Use a disposable cheap android phone to host your bitcoin wallet and load only 1 identity on it.
Create a fake identity that cannot be traced back to you. Buy burner phones cash.
Remember, making one mistake will cause your anonymity to fall.
Protecting your Operating System
Use a secure Operating System with TOR
Your computer can be compromised to leak your identity. Even without being compromised, it leaks your identity all the time. Not only do you leak data but the unique setup of your computer leaks your digital fingerprint to any site that wants to track you (article here). If you want to test this yourself, check out Panopticlick.
Hopefully you now agree that traditional operating systems aren't secure enough for the purposes of anonymity. You will need an Amnesic Incognito Live System called TAILS. This is a free operating system that you boot from a USB key that is fresh everytime you use it and doesn't leave any forensic traces on the machine it was used on.
Tails also routes all internet traffic through TOR or I2P (use TOR). So you will use the Invizbox Go to tunnel to Switzerland and then you will use Tails with TOR to get to the dark web.
Tails is built for privacy and has a specially designed browser to minimize tractability. Ensure you follow the instructions to double check the integrity of the file you download. You will then need 2 fresh USB keys to built the final Tails USB bootable system.
You will have to make sure you laptop is compatible.
Protecting your transmission
If you are going to use email, then make it as secure and anonymous as possible. Use a free Potonmail account (review here) via TOR.
Anonymize your style - Stylometry
Well funded threat actors and nation state intelligence are able to identify people using stylometry. This is a technology that analyzes your writing style and then uses this knowledge to de-anonymize your content on darknet sites.
Think of stylometry as a digital fingerprint built against your writing style (how to evade stylometry) . You may also want to checkout the Anonymouth tool from The Privacy, Security and Automation Lab (PSAL) Drexel University, Philadelphia PA.
Using Anonymouth will allow you to engage online while minimizing the intelligence community's ability to perform stylometry on you.
Michael Moore should setup a TOR SecureDrop service
The best way to send information as a leaker is to use a TOR service hosting SecureDrop (create by internet privacy advocate Aaron Swartz). It is an encrypted dead drop used by journalists to collect info from whistle-blowers while protecting their identity.
The Freedom of Press Foundation has taken over the project since Aaron's death and helps media organizations install and run the tool. the FPF is addressing all of the shortcomings of the original tool
Don't trust printed leaks
You may be thinking printing and mailing is the best option but it isn't. Many printers have a hidden feature which adds invisible identification to every printed page (see EFF article here). These "invisible" yellow dots allow intelligence agencies and police to track down which printer printed a document. Recently this technique was used to track down an NSA leaker when a picture of a leaked document was show by The Intercept and the NSA found out the document was printed on one of its documents.
If you are interested, you can read about this technique here.
Simply following the basic instructions on the Trumpileaks website is irresponsible and dangerous. Ask yourself what would be the impact if the leak was tied back to you? Are you willing to live with the consequences?
Even with strong knowledge and good security hygiene, perfect anonymity does not exist on the internet. If you are determined to leak, learn how to do it and take the above precautions but know there is always a risk you will be discovered.