Not posting mine as no pics and it was a 90's horror! Puff sleeves etc
However, I later went on to work in the wedding industry. My top tips are:
Try ALL shapes on - these are not dresses we wear ordinarily and so we're not used to which style suits which body type etc and even that is just a guide. Height, body shape, posture, colouring and hairstyle all make a HUGE difference. I've had many an occasion where a bride has been "certain" a particular style won't suit her only for me to suggest they try on a particular dress which I knew how it hung etc and that was "the dress" for them!
When trying on bear in mind most dresses come in a variety of colours, not just the usual bridal white/ivory/Cream but bold and pastel colours too so even if you aren't up for these colours but a wedding dress assistant suggests you try on one in a weird colour try it anyway, and vice versa if you're looking for a particular colour too
Also bear in mind the lengths - they're designed for tallest likely scenario because it's easier of course to remove length than add it
Don't be put off by a minor detail that can be altered - good specialist bridal seamstresses can work miracles! Wish I'd known that for my dress as I'd have had the sleeves and neckline changed and the train removed. Was very naive/ignorant at that point. I've seen dresses become almost unrecognisable to the original design by alterations to:
Neckline, backline, sleeves/straps, fastenings, length, hemline...
Also if you find your perfect dress as a second/second hand (best time to shop in boutiques is normally just before Easter as they're offloading "last seasons" designs to stock the new ones and samples they're getting rid of etc are massively reduced) but it's the "wrong" size don't be put off there either, they can be taken in by as much as 3 dress sizes and dependent on seams and style let out by 1.
If modesty is an issue while most dresses are strapless now (annoying I know but again it's because these are easier to alter) as well as adding sleeves to the actual dress you can also add stoles, boleros, coats and capes (my mum had a short cape for her wedding but these are less fashionable just now) which are then easily discarded for the reception so you're not too warm (I had a spring wedding too and ended up with it being a crazily much warmer day than expected!)
My word of WARNING would be NOT to use a high street/ordinary alterations place - bridal fabrics are often delicate, need careful handling and it's VERY easy for things to go wrong! I've directed a fair few heartbroken brides to specialist seamstresses after their dresses were damaged/badly handled by amateurs (in the bridal dress making sense not necessarily amateur seamstresses) - put it this way, my aunt was a professional seamstress for over 40 years but not in bridalwear and even she wouldn't take on ANYTHING but the most basic tasks - eg adding/removing straps - as while she's a fantastic seamstress she's not trained or experienced in this area.
Good luck in finding the perfect dress