First let me say hello. I've been on here many times for years to come had some past accounts, but cant remember the password or the email passwords to em lol. So i decided to make a new account and be a part o the community. Jason Manley, Davi, Android, Marko, and to any other common pros and amateurs who made this site what it is, thank you very much for being able to create a community where the common artist can get more feedback. Anyway my contribution so far...
I found these great tutorials at www.productdesignforums.com I figured some people might want to look at them and specific tips on technical drawing and perspective. This site has many great tutorials as well but I figured it lacked a bit on themechanical and technical side of things such as robots, or technology etc etc. Hopefully this hasnt been posted yet.
Tips on how to improve your drawing ability
Top ten lies told to naive artists
Pen and Ink Rendering
Understanding and Communicating Form
Quick Sketching in Painter
MIT class notes and videos on marker rendering and perspective
Car Sketch Tutorial
Making a perspective grid for sketching photoshop
How to choose an appropriate perspective
Some good advice on finding supplies for marker paper and the like
Theres much more resources on that forum, and it can help a lot if you would like to draw mechanical science fiction and environments.
The GREATEST tip ever told is Study, practice, study, look, look more and Practice practice practice. Remember to always challenge yourself as well.
Haha, these things may sound empty coming from me because I'm nowhere near the skill level of a lot of the people in here or at productdesign, but I do like to help.