When adding new cards, remember that the card's average energy cost is 1.5 with Snecko Eye. This means that cards costing 2 or more become better value than normal, and that cards costing 1 or less become worse value than normal.
If your deck's average energy cost is less than 1.5, then your average energy cost will go up with Snecko Eye. If that's the case, you shouldn't pick it unless you have time to build around it or unless you have enough card draw to mitigate high-cost hands.
Snecko Eye has a synergy with Ice Cream; you should save Energy on turns when your cards' costs are low so that you can afford turns when your cards' costs are high.
Snecko Eye works well with Gambling Chip; you can discard any cards with costs that are randomized too high to play, making your opening turn that much stronger.
Cards with variable energy cost (Masterful Stab, Blood for Blood, and Force Field) will have their costs replaced by randomized costs when drawn. Taking damage or playing powers will increase or decrease the card's cost only for as long as it is in your hand, as it will be randomized again the next time it is drawn.