Simple score voting is the only answer, and it can be completely described in one short simple sentence: Give no vote at all, or from one to ten votes to any number of candidates you wish (up to some reasonable limit, say 20 candidates), and then simply add all the votes up.
Also we must abolish election machines (such as voting computers). If they make casting and tallying 10 times faster, they make organized cheating 10 times easier as well. Which can we truly afford?
One could say that (strategic) simple score eliminates 90% of the spoiler effect. To illustrate: if a voter gives 10 votes to Nader and 9 votes to Gore, it is simply obvious that, if Nader does not win, the voter has only sacrificed exactly 10% of their voting power. Not 100% as they would have had they been forced to use the usual single-selection ("faux plurality") voting method.
No fancy math is necessary to compare and contrast it to every other option for effectiveness and simplicity, including single-selection (aka "plurality," our present "system") Condorcet, Borda, IRV, Range (with its tricky "averages"), Approval (which is not adequately differentiative for choice of candidates), etc. These absurdly complex "alternatives" are merely make-work for scholars and lobbyists who usually do not really care at all about the general welfare of public.
The simple score method is the very simplest, since it only allows from 1 to 10 votes to be given, not from 0 to 9, or 0 to 10. That is simply another complication. It also has no vote-averaging that seriously complicates the "range" score method. I also seem t be the only one to point out that voters should always vote artfully (aka strategically), not artlessly or heroically (aka "honestly" or "sincerely"). The party-based versions of proportionate representation have failed completely in places such as Germany.
And the people MUST vote strategically -- NOT artlessly ("honestly", "sincerely")! Do the Senators and judges act with honesty and sincerity? Do they vote heroically? Take a wild guess!
And why do you suppose they don't have just ONE money-empowered candidate or party? Something to think about?