A few of yours plus:

ADMINISTRATION

• Active Admin - Simplify the way you manage your website and your models.

CSS

• bootstrap. Add twitter bootstrap.

HTML

• haml. Save time and gain clarity with your html code

• httparty. Makes http fun again! (not my words but pretty accurate)

API

• apipie-rails. Easily document your API

MISC

Of course don´t forget. Devise, sidekiq, stripe ...

I program in RoR and use bootstrap. I´m not very good with css so i usually buy a template for 20€ based on bootstrap, use the styles that i like and modify those that i don´t. I used to try to create all the styles from zero but that could delay the shipping of the project for a couple of weeks.
Now i just try to launch ASAP and doing that allows me to be faster.

So i guess my answer is i dont know and probably just practice, practice and more practice.

You can start with 'learn while you poop' de @swizec . www.youtube.com/watch?v=JnMXu…

Good points to consider. That will help you to follow the days you feel everything you are doing is meaningless.

I think i would. Had to be out two weeks and have no idea what projects were launched. Also could be interesting knowing about the launch of this projects and other information after launch like MRR, active users in the projects.

Linode, heroku.

Agree. Spanish native speaker but most of the things related to technical stuff just use English.

Go to meetups related. Talk to people. You can get many ideas on what is interesting and what problems there are. Then choose one and build a fast mvp. Then go back to meetups and show them the mvp.

Looks like a good solution for selling products online. For the fees in the card i would say they have stripe integrated.

Leaving businesses makes it easier. That´s another option to consider.