Hi. What brand and size of needles are you using, we here have found some are better than others.
We all get the occasional bruise from time to time but it should only be occasional.
Just incase you're technique needs a little tweaking I've found a link on here.
https://www.diabetes.org.uk/Guide-to-diabetes/Managing-your-diabetes/Treating-your-diabetes/Insulin/
I don't know if this applies to you but I have some spare flesh lol. I've found slightly stretching my skin rather than pouching on insertion then remove hand till your ready to remove the needle , then slightly stretching the skin again is best for me, don't try it if you don't have any spare flesh though .
Let us know how you get on.