The way video poker strategies are usually expressed is a list of hands you might get on the deal, in order from best to worst. For any given hand, look up all viable ways to play it on the list and go with the one that is listed first. If you don't see a play listed, like suited 10/A, then never play it. Here is such a strategy for Jacks or Better.
An inside straight is a would-be straight with a hole in the middle. 9? 2? 10? 8? 6? is an inside straight because only a 7 will turn it into a straight. The distinction between outside straights and inside straights is important because in Jacks or Better we will never try to turn an inside straight into a straight. It's too hard, since we have only one chance of completing the straight.
A kicker is simply a card from a certain set of cards. For Double Double Bonus, four aces pays 160 for 1. However, four aces with a kicker of a 2, 3 or 4 pays a whopping 400 for 1. This is two and one half times what is paid for four aces without a kicker. Getting four aces with a kicker pays half as much as a royal and it occurs two and a half times as often. Four 2’s, 3’s, or 4’s pay 80 for 1. Four 2’s, 3’s, or 4’s with a kicker of an ace, 2, 3, or 4 pays double that or 160 for 1.
Despite the importance of finding the best machines, most players don't. That's why casinos can offer both decent and lousy machines in the same casino and be confident that gamers will still play the lousy ones. They have to keep some good machines, otherwise they'd lose all the players who know what they're doing. But most of the machines will be bad, and most gamers will play them anyway. Heck, in Vegas even casinos and supermarkets have video poker, with absolutely terrible paytables, but people will still play them rather than going across the street to a casino where they can get seven times better odds. Go figure.