Don't wait for senior software engineer guiding you. They are either not good or they are very busy! (if they are good).
If you genuinely want to learn something, i suggest you take up a hobby project on your own - and put it open source!
You will gain following:
- With freedom and interest - you will pick a subject to learn about something.
- As you try to put a whole product together - you will inevitably learn the real significance on how design and architecture work.
- As you collaborate with people - you will get people's feed back on what is really important.
- If you happen to built few iteration of work and release code- you will learn principles of software development process.
Of course, other rewards are all out there -if your product is some good.
Given your comment, i felt i have been a bit biased. But if you have been through the process of making a whole product - than it is time look something bigger and deeper. I guess, now i knew what you are asking for.
I would suggest following area to master - and leave upto you how you plan/implement your learning.
Getting to know more about broader perspective in Software Architecture - i know so many people would recommend that and i am not going to over emphasis. But i think the point i am making is to look at Architect role to visualize how things evolve when product grows big. Lots of literature are out there pick anything to start with- but this is very crucial step that will transform you.
Getting to know many other technology aspects - have you been curious about how - OS kernel, Database, Java or .NET run time, File systems, Web servers, browsers, distributed systems, - the daily stuff we use- how does it work from inside? How is their architecture? what are the key design criteria.
Learn about technology adoption process. Many people will differ on individual opinions if you ask why would JAVA or .NET is better and why did CORBA never achieved what web-services did, and whether Android will overshadow (or kill) iPhone upcoming generations. As engineers who are so busy thinking how stuff works - we often need to get above and see deeply as to why certain things work in life and why not.
All of these would need you to pick specific topics of your interest and get little more than web crawling to get down to reading books or go deep in the subject.
I know i have give you rather broad answers than specific tips/pointers - but that's precisely the idea.