Looks really cool and promising.
Would love to see tips about upcoming Marble tournament before it starts though, just to test if it's of any use to inexperienced players.
Constructive criticism:
The most important things (in my opinion) are lacking. There are some practical tips that can be given and that aren't as obvious as "this unit beats this unit". Example: many players think that catering in a first few rounds is a good idea, because costs are low....which, of course, is not the case because exactly in these rounds fights are the easiest (it's nearly impossible to lose even with auto-fight). Every penny counts, so it's better so save goods until the point when fights can't be won at all or are just hard to win. You could throw in exact numbers about army strenghts in each round just to support this statement.
Also, looks like you picked the most perfect enemy comps to illustrate fights (at least image-wise). That can be extremely misleading... add some not so perfect or "hard" comps, that consists of enemies that compensate each others weaknesses, for gems let's say 3 heavy melee units, 3 light ranged 1 heavy ranged. Proper suggestion would be that players shouldn't fight against such comps, at least in 3+ rounds and using auto-fight.. Best option would be to cater them.
Next thing, more advanced tips, like:
1) explanation of terrain: at least units placement on the battlefield;
2) "always strike first" rule;
3) testing the waters with high initiative unit (might confuse many players...so..might be an overkill).
Of course, these ones are not exactly oriented towards specific type of tournament, but are quite general.