Blazing Star has always been a favorite of mine. I've been playing it since 1999. I never really paid much attention to the score side of things, but I loved the intro, the graphics and music, and just everything about it. I'd have to agree that it still has a lot of old school charm but a lot of good modern touches like scoring mechanics. When I did the research for the writeup and after my first few runs, I saw that there was a lot more to the scoring than I originally thought.
ExedExes - 1,843,060 - Aryustailm - Stage 3 - MAME

Got the A grade on the first 2 stages, then proceeded to lose all 3 lives a minute into Stage 3. So much debris and bullets to deal with. There's more to this game than one would think. Love it!
To answer your question fvgazi, it's best to wait for more enemies to make the screen. There are plenty of opportunities to do so in Stage 1 and 2. Anticipate when they arrive so you can have a fully charged shot ready (when you see the word DANGER, it's a good chance to see many smaller enemies.) Also, try not to break the charge shot unless absolutely necessary.