Don't feel discouraged by other games. You are being presented with a finished, polished product that also started in a lackluster form. It's without a doubt a step-by-step process, adding progressive detail. Graphical special-effects are the "post-production" type of work.
Complementing what Simon said about the additively-blended particles, take care with...
The transparency fall-off so you get the precise glow amount you want;
The animation the particles perform, so you have a convincing and entertaining special effect. You'll need a dedicated particle animation editor for this - especially one which allows quick iteration for you, so you can try and tweak differents parameters and see what looks best.
'Variation' comes to mind - having different animation sequences (or parameters) for the same special effect, chosen at random to make things more organic and unpredictable.
If you have the time budget, after you're done making a special effect don't watch it again for an entire week or more. Next time you play it you'll have a new, fresh look of it and be able to notice and tweak things you couldn't before.