Trying to memorize the locations of all the Sol Towers to improve my scores in Xevious is really difficult! I already knew where the 4 flags were, but there's so many Sol Tower spots to memorize! =O
Such a pain in the ass.. You have to give yourself plenty of space to bomb their location, wait for them to surface, then bomb them again! And not get shot in the process!
It took me about 4 hours of practice and studying area maps as I played last night, but I've finally managed to memorize the locations of all the Sol Towers up to Area 14; which is the farthest I've ever made it in the game. =)