For instance, I'm an ardent horse lover and nothing pulls me out of a historical romance more quickly than inaccuracies about saddlery etc., or riders who 'shake the reins' to encourage the horse to move forward. My pet 'peeve' is heroes who always ride stallions, (even worse if it's a heroine). Now don't get me wrong, a stallion can be an amazing animal to ride, and I've ridden a couple who were a dream – but on the whole they're not practical for every day travel. Apart from usually being very spirited and only suitable for an experienced rider, they do tend to have a 'one track mind' when it comes to mares, and you couldn't just turn a stallion into a field with other horses without a few 'fireworks'.
In historical times a woman would usually ride a mare or gelding, and although it might seem like a good idea for your feisty unconventional heroine to ride a stallion, bear in mind that this would not be 'the norm' and very few women would actually have ridden an 'entire' animal.
This was especially true in medieval times when noblewomen normally rode a light, gentle horse known as a 'palfrey'. It's different with warhorses or destriers, ridden by knights though,when a stallion's fiery and aggressive nature would be an asset on the battlefield.
These days with so much information on the Internet, it's relatively easy to find out the details you need to make sure you don't slip up on a 'horsey' detail, such as which side a bridle would be buckled on and how many girths there are on a sidesaddle, and it's pretty much the same with almost any subject you need information about. Just Google the subject and you will usually be presented with a number of sites. Personally, I love Wikipedia, but don't take everything there for Gospel, although it's a fantastic source of information it's not always one hundred per cent accurate. I find the best sources of information are websites which concentrate solely on the subject you're trying to research.