Hi there, lots of great tips already.
My Obstetric Physio said to remember the mantra "short skirt, no knickers" !
i.e. always behave and manoeuvre yourself as if you are wearing a short skirt with no knicks (which you do not want to reveal!), especially when getting in and out of cars. Splinting your legs is very bad for SPD.
Make you movements as symmetrical as poss and sit down to put shoes on.
My first pregnancy and long after with SPD was just awful and it was discovered too late, but for my second my local hospital ran a pregnancy, physio pilates class which helped a lot.
Lastly, for people who have had it very badly, consider seeing a specialist osteopath in case you have some structural problem which is exacerbating it.
I couldn't work out why my SPD never really went away and didn't realise I had had a twisted pelvis from bad posture (for most of my life) until four years after my first was born. The Osteo I saw spotted it straightaway, yet I had spent hundreds and hundreds of pounds on physios and a previous osteopath all of whom only ever managed my symptoms. If I'd seen him much earlier he could have possibly saved me from the interventions necessary for my births. I didn't go because he was miles away down in Kent, wish I had gone earlier now, as he is inexpensive and can make a lot of difference in a few sessions.
His name is Quentin Shaw and he is a world renowned expert in his field of classical osteopathy for SPD and spinal problems. He changed my life (and my posture!). He's in Tunbridge Wells which may not be local, but he has women who travel from Scotland and Ireland to see him because he's so good. He's had women come in in a wheelchair and walk out on crutches after one session / come in on crutches and walk out without them etc., and then continue to improve. (p.s. I not his friend and don't work there or anything!) His colleague Matt is brilliant too.
Hope it goes away quickly for you and everyone else on the thread, it's the most debilitating, shitty, miserable thing and so hard to explain to anyone who doesn't understand.
Links:
Tunbridge Wells Osteopaths
Pelvic Partnership for advice