I have followed many tutorials and instructions, does anyone have any tricks or tips on how to get the tops of my BC cakes level?
Using a tip to pipe BC on cake works for me.
Some use the icer tip, and I've read a tutorial of (oh gosh can't really remember her nick, it was Tutu-something) a decorator here using a no.18 tip; I just use any numbered tip of a medium-sized opening (1M or 2D can do) to pipe BC on the sides of the cake as well as on top.
I find using a tip first to pipe even amount of icing all over the cake saves me time as I do not need to crumb coat my cake prior to icing it.
Right after piping all over the cake I use a scraper for both the sides and top (watching Edna's video will help greatly, too).
The upside down method is great, especially when you use ganache with it.