I'm a champion online shopper and have many methods. It took me quite a while to learn how to do it. But the main secret is simple: Listen to Angie. Her top picks often include items from stores that we can access. And her detailed descriptions can save you from ordering things that simply won't work on your frame.
The first step is make some big-city forays in order to isolate a few brands that are likely to offer a decent fit. My actual size is not always on the floor in stores, or not in a colour that interests me, but I try on anyway -- even if I can't find my size, I can guess what my size in that brand will be, and can see which cuts are promising and which are less likely to work.
When considering online purchases, I also pay attention to whether or not there are free returns, and to how long the return window is. I prefer to order from places that offer free returns unless I very much want the item and this is my only option, or I am already sure it will fit (because it's a repeat style or duplication) or I know I will be going to the city within the return window so I can take it back to the store then.
Here are my experiences and recommendations for what they are worth.
Nordstrom. Now that we have stores in Canada, it's not necessary to order online and use Borderfree, or to cross the border and shop in store. I mainly shop there during the NAS. I got a card and I check the pre-sale for items that interest me. Once I've selected my key "wants" I will phone one of the stores and ask if the item will be part of the Canadian sale. If it is, and if it's available anywhere in Canada in your size, they will mail it to you free of charge, at the Canadian sale price, which admittedly is not as reasonable as the US sale price, but is still a bargain.
You collect points in Canada which are separate from your US points (if you are also buying in the US).
I do continue to order online from the US site and sometimes have the items shipped to a US address, or sometimes a kind American friend helps out by shipping from their home.
Most of my fall shopping is now done well in advance, thanks to NAS. Returns are the same as in the US, so you don't need to rush back to the store if you're not able to do so. And Angie's recommendations are so spot-on that I rarely make a mistake any more with my NAS orders.
You can also order from The Rack. I did this not long ago and it worked out extremely well. It went through Borderfree, I guess, but the cost was minimal for some reason.
The Bay: The website is antiquated and awful to use. I have not been shopping there for the last year and a bit, but I do visit the site from time to time and it hasn't changed. However, the selection can be fair to good--far better than in-store even in the city -- and deliveries are free over a small amount. Returns can be made for free in store. I am not sure about mailing costs -- I'm always able to get to a store in time. I used to get most of my footwear there and other things also. They carry Lord & Taylor.
Gap/ BR: This is an easy place to order from. Free delivery (over $50) and free returns. Deliveries can be very fast or very slow, depending -- they seem to be using UPS right now so it is fast. When Angie recommends an item from here that is in line with my needs, I always check it out.
J. Crew: Delivery costs $12 but they often have free delivery days. It does cost to make returns but you can also return in-store, so I try to time my orders for when I'll be going to the city. Duty is already included in your total. Items take a bit longer to arrive than from BR.
Zara: I strongly dislike in-store shopping at Zara, but online shopping there is excellent. Free delivery and returns (you can also return in store). Delivery is extremely quick to my address, and they package items nicely. I return far more than I keep, but that's okay. I still get the odd item. Massimo Dutti is similar -- I haven't actually ordered from them -- only bought in person. But it's the same company.
Club Monaco: Free delivery over a certain (easy to meet) amount. I usually return in store so I can't remember if they make you pay to return -- probably.
Aritzia: Annoyingly short return window. Or rather, their return window is 30 days for refund but their initial delivery (to my address) is so slow that there are usually only 15 days for me to get it back, which often isn't enough for me. I find the fit of their items off anyway. But I'm sitting on a huge credit for an ill advised order last spring that I was not able to return within the refund window. Sigh....
Shopbop: I've actually never ordered from here and I am not sure why! Free delivery and returns and lots of selection -- but pricey items. I need to check it out more frequently.
Simon's: Again, I haven't ordered, mainly because I don't know how I fit their clothing. I need to do an in-store try on when in Montreal some time. Gaylene is the Simon's expert here.
Bloomingdale's, Nieman Marcus, and Sak's: I haven't ordered from here but Mr. Suz has. the returns seem complicated but perhaps that's just because he left the stuff to sit for so long!! I guess it goes through Borderfree so there will be costs associated with that.
Mark's: Yes, you can order from there! I don't shop there but bought a ton of stuff for my daughter. I was able to return in store.
Altitude Sports: This is a fantastic place to do business with for puffers, fitness wear, other coats. Fast delivery, superb customer service on the phone. Free returns if you are a member.
MEC: Slower delivery than Altitude but useful if you're a member.
Land's End: I used to order my mother's stuff here. It was pretty straightforward and I would just send back whatever didn't work. I think I paid for returns, but sometimes had a free return label. LL Bean and Eddie Bauer also deliver but it's more expensive.
Footwear: I won't list all the stores, but there are many now that deliver for free. If you look up the brand or shoe that interests you, you'll find options. Prices are of course higher than in the US.
Independents/ Small or Speciality Canadian companies: Don't rule these out. They often deliver. And you get something unique and special. There are some amazing companies making bags, belts, coats,
and clothing. For example, the Toronto design team Comrags has an online store. Most of our well-known brands have an online presence -- from Roots to Mackage. If there's a brand that interests you, look them up! They very likely can send it to you.
I tend not to order from Loft or AT because the prices are so high when adjusted and returns would be expensive too. Ditto for WHBM (I'm not even sure you can order from them, actually) and Anthropologie. But part of my reluctance is also because I'm not sure how the latter two brands fit me -- I need to do more in-person sleuthing.