Hey Gems, you ask very good questions. Your instructors would be a good first place to start to ask them, to get their insight into the industry...
Here's the thing. you've expressed interest in Fashion and Bridal, two totally different make-up styles and disciplines. Working in retail will not help you get into the Fashion and Brida worlds, nor will you learn those styles in a retail environment. However, there is nothing wrong with working in retail in order to gain product knowledge, learn conflict resolution, and learn how do a business plan.
Now you have to make a choice on where your focus is going to be...
The answer to these questions will only be answered by you by taking a longer, more comprehensive make-up school and by also asking your instructors about their experiences working in the field.
Most students who graduate from a 6 month to a 1 year make-up school, have a large make-up knowledge base that they can work in various make-up styles at the same time. For example, they work for MAC p/t during the weekday and they do Bridal work on the weekends and they might even do shoots on their day off during the week to work on their book.
As for where to start, Make-up schools have resources that will put their senior students in touch with industry professionals and they go from there. Most schools have a professional reputation in the global industry that they have to maintain, Like MUD and Complections, thus they only give their top students introductions.
Building your kit is a long, slow and expensive process that will involve your entire career.
As for how I started out, I quit my job and enrolled in a well known industry recognized make-up institution. (Film unions such as IATSE and NABET only take MUA's from schools they recognize. They don't just let anybody work on Kristin Stewart, Bruce Willis, Julianna Moore, Laurence Fishburne, Lindsay Lohan, Jodi Foster... etc) Agencies are a little less strict, but models and celebrities are very high demanding, so they always request the best of the best MUA in whatever city they go to for press pro. And those best of the best MUA's have all gone to accredited schools... Well, most of them.
After I graduated, I worked in retail p/t to help build my kit, the other half of my time I was doing testing, after 5 years of constant testing, I finally got into an agency and started getting paid gigs. Like I said, the Make-up Industry is highly competitive and you're vying for spots that Pat McGrath, Alex Box, Scott Barnes, Jackie Shawn, and Teena Black etc are competing for.
Yeah, I did my fair share of weddings, but I had enough of the bridezillas, and the constant mind-changing after the consults, Yes, it IS a cash-cow if you do weddings fulltime and can deal with all the drama-rama. After awhile, I knew that wasn't for me.
I loved Editoral Fashion, so I focused on that. Unfortunately, that part of the industry is very, very difficult to get into, It took me a good 7 years to get established in it. However, some MUA's get into it rather quickly if they know the right connections, and you have to be prepared to swallow a few bitter pills on the way up.
My personal experience: I had 10 years doing EF's, I am at the top of my game and along comes a 20 yr old with barely 6 months experience and she got all the top gigs, Why? Her mother knew the Editor-in-Chief... Such is life.
I now do primarily film and tv work. I got into it after a collegue of mine gave me her gig that she couldn't do due to a scheduling conflict, and have been doing it ever since, and that was 10 years ago.
The whole point to all of this, is be pateint. You will get all the practice and experience you need in a school environment, that it will just give you enough knowlege you need to work in the industry. And from then on, your REAL make-up training will begin. In other words: You need to crawl first before you can walk and then walk before you can run, only then you will have at least a chance to run along side with the big boys.