People sometimes, when you tell them about correct hijab, accuse you of judging the sister that isn't properly covered, saying we are all at different stages in our hijabs. I don't think that is a valid excuse to cancel out nasiha, and I understand different "stages" of hijab more than most born Muslims. I think I can speak on the subject. But before you get all huffed up on me:D please read all that I have to say in its entirety.
Before I even became a Muslim and made my shahada I covered my hair with hijab. It is a command for all women who believe in God, Christian, Jewish, Muslim... so as I learned about Islam I knew it applied to me before I even made my shahada. Every idiot out there knows Muslim women cover their hair so even if I didn't know why beyond the Christian reason for doing so, I did cover mine. Unfortunately, that meant that I did things in my hijab that I regret still. But I made clear to people I was thinking about becoming a Muslim and hadn't become one wholly yet. Even as I took my hijab on and off (no shahada yet ladies) I never told people it wasn't a religious requirement. I wasn't qualified to speak on the subject so I didn't try and be an authority on the matter. I wish others did the same.
Anyways, when the time came and I did make my shahada, (I had only read an English translation of the Qu'ran through once) I stopped taking my hijab on and off and though I did have some trouble learning how to wrap it so it did not slip off my head and so that it covered the chest (I only read the Qu'ran once but got the " cover the chest part"), I managed okay. What I DID struggle with was learning how to make my existing clothes and limited financial means "cover". I understood from reading the only existing online real hijab fashion blogs http://www.preciousmodesty.blogspot.com/ and http://caribmuslimah.blogspot.com/ (both African-American sisters running the sites---one a convert and the other a born Muslim) that all the skin had to be covered and the clothing not too tight but I didn't have much to work with. I mean, as a former classroom teacher, my clothing was more modest than most of my non-muslim friends, but it wasn't hijab. The best I could come up with were button up tops (I had a red silky taffetta one and a white oxford), a pair of white trousers (not overly wide but not skinny-cut), a pink brocade pencil skirt, a white bubble mini skirt, a long beige mermaid cut skirt, more stillettos than Carrie Bradshaw, a classic beige trench, and a white trench. I also had my grandma's vintage diamond clip on earrings which I wore as hijab pins before I was introduced to stick pins. I wore the pants under the skirts (white bubble mini and pink pencil skirt) and wore the button up untucked in on top. I realized my butt showed like this and started wearing the trenches over top. Even in the long skirt, the shape of my bottom hung out, so I started wearing the trenches as an overgarment. Even with a long top I still didn't feel comfortable without the extra layer of the trenches.
Men (non-muslims) still tried to ask me out though, even when my clothing was satisfactorily loose and what most hijabi style bloggers consider pretty flawless hijab such as below: loose fitted top, modest fitting skirt, hijab covering the chest (just not in this shot cuz it got stuck on the coat)... It would have been hijab to me even now if the trench were closed but since it isn't I don't consider it hijab, having read the Qu'ran more than nine times now the whole way through, alhamdulilah and subhanallah who'd ever have thought I'd manage it? I def. couldn't have without the aid of Allah subhanhu wa ta'ala. Anyways, the second reading came up with a command to wear jilbab, and though it took me a while to research exactly what jilbab was, I started wearing an overgarment as soon as I understood. Alhamdulilah. As soon as you understand something you should do it. If you don't understand it, and you are doing it anyways, be sure not to give advice on the subject of any kind or you risk misleading people. If you understand it and feel is an obligation, but are not strong enough to do it, explain that to anyone that might ask, and ask them to pray for you to do what is right. Dua always helps.
There are no "different stages" in hijab besides lack of knowledge and if you lack knowledge you don't have Islamic hijab yet unless you were raised with it. Once the knowledge is there the only option you have besides applying that knowledge is asking Allah for the strength to. It doesn't excuse you for not making up the obligation, but it certainly is more helpful for you and if you ask for help instead of making excuses to everyone out there. Hijab gets easier and easier, the closer you are to wearing it according to the sunnah. May Allah make it easier on all of us to wear the correct hijab, ameen.