I was wondering if anyone had any advice or tips on how to use the time productively during lunch and breaks. I'm generally just browsing the web or working on some projects but never manage to get anywhere. Is there anything that you guys do that generates result both in terms of career development and getting work done. Also how do you keep doing it or stay motivated as I tried learning new things or following tutorials but started drifting off again.
The brain needs rest. The vast majority of people simply can't operate at a high level for 8-10 hours straight. The best thing you can do during breaks is to actually rest up. You'll be more productive and feel better.
A good thing to do for "career development" is to socialize. Being liked and knowing your coworkers, bosses, etc. is important for career growth. You might learn a new skill if you just stay at your desk all day and then get passed up for promotion because your co-worker has been actively engaged with the team and making a name for themselves.
Edit: Just saw your other questions about being an intern. Definitely walk around and talk to people. As an intern you can learn a lot about other projects, new technologies, and how companies/teams operate by being more engaged in your team. That kind of experience you can only get at work. You can pick up skills on the internet any time.
During lunch and breaks, eat lunch and take a break. A short break can increase your productivity afterwards.
If you're really in the middle of something, hot on the trail of a bug, in the groove and cranking the code, or whatever, skip the break. The point of a break is to give you a chance to catch your breath and relax a bit. If that would help, catch your breath and relax a bit. If not, just keep going.
Trying to cram some other deliberate activity into a short break defeats the purpose, and probably doesn't give you enough focus time on the activity to do much meaningful.
You don't have to "sit still" to take a break. It just requires that you do something that isn't programming. When the weather is nice I like to walk as I have lunch. The physical exercise leaves me with a lot more mental energy when I return. It especially helps if I have been banging my head against a problem for a while; often I come back with some very good ideas on how to tackle it.
If the weather is bad, listen to music. Read a good book. If you don't have a lunch room or don't want to go, eat at your desk. If you are worried about how it "looks" for you to be at your desk "goofing off" you might bring a large and visible lunch timer so that people know when you are taking lunch (I had to do that at one job when I found out that people were reporting me).
If you feel you absolutely must keep grinding away even during your lunch break, try something unrelated to your normal work flow. I like to browse through www.stackexchange.com for interesting technical issues. I learn a lot from the answers and sometimes I can score a few points :)
Like you, I have a tendency to get bored by tutorials. I need actual projects to keep me interested. Work on some kind of pet application for your own use (My latest project is an application to import my personal credit card and banking information into an Access database and output budgeting information). Start a lunch club with coworkers where you share knowledge or work on a communal project over lunch.
Get out of the office. If you have any errands to run like buying some shampoo, a new book that came out or anything like that why not go do it? You'll buy yourself more free time after work by getting something productive done. The weather has been nice so I've been eating my lunch in the park lately and then reading a book for the rest of the hour when I don't have any errands.
Studying work-related topics is a noble pursuit, but you may find that you can get a lot more done with a bit of a mental break and some fresh air mixed in and not be down any productivity overall. For a shorter 15-minute break take a walk around the block to clear your head.