First of all, the building blocks you have to choose from.
Your own list, Likud Beitenu, the one you set up together with Avigdor Lieberman, is expected to gain between 35 and 40 seats. All other parties will be markedly smaller. There is no party in the 20-35 seats range.
Shelly's Labor Party is hovering between 15 and 20, competing with four parties between 9 and 15. These are Tzipi Livni's Movement (that's actually its name, The Movement); Ya'ir Lapid's There is a Future (contrary to those who believed that the world would end last week); the oriental-orthodox Shas and Naftali Bennett's The Jewish Home.
Naftali Who? Bennett is the great surprise of these elections. He appeared from nowhere, a successful high-tech entrepreneur with a tiny kippa, who has managed a hostile takeover of the moribund National-Religious party. He has succeeded in throwing out all its venerable leaders and become the sole boss. Within a few weeks he has doubled the party's share of the polls by outflanking Netanyahu on the right and voicing opinions which some consider outright fascist.
Where does Bennett get his supporters from? From the Likud, of course. Bennett was once Netanyahu's office chief of staff, but made the fatal mistake of running afoul of Sarah'le, the Boss's wife (or, some say: the real boss.) Now a furious battle is raging. Bennett accuses Netanyahu of supporting the Two-State Solution (which nobody in Israel and the world believes) and Netanyahu attacks Bennett for announcing that he, as a soldier -- a major in the reserves -- would disobey an order to "remove a Jew from his home" The "home" in question being, of course, a settlement on Palestinian land.
Since the Likud itself has become far more extreme since the recent primary elections, and since the addition of Lieberman's cohorts makes it even righter, the looming confrontation with Bennett will be a riveting fight between the Extreme Right and the More Extreme Right. There is also a Most Extreme Right: the disciples of the late unlamented Rabbi Meir Kahane, who, however, will probably not pass the two-percent minimum hurdle.
Coming back to the party lists: apart from the Likud and the five "medium-sized" parties, there are six small parties. The most important of these by far is the Ashkenazi Orthodox bloc, Torah Jewry. Then there is Meretz, the only Jewish party that admits to being left-wing. Of equal size are the three Arab parties (including the Communists, who are mainly Arab but who also have a Jewish candidate). And then there is poor Kadima, the largest party in the outgoing Knesset which is now struggling to overcome the two-percent curse. Sic transit gloria mundi.
SO NOW you can set to work. Remember: the aim is 61 members at least.
The most natural coalition would be an alliance of the Right. Likud-Beitenu, the Jewish Home, Shas and the Orthodox will probably add up to around 67 seats. They could implement the policy of rapidly expanding the settlements and preventing the creation of a Palestinian state, keeping up the eternal occupation and not giving a damn for world opinion.
The drawback: this composition would put an end to any pretense about your adherence to the Two-State Solution and your desire for peace. You would stand naked before the world. Israel's international status would plummet, with possible dire consequences.
Also: you would be open to permanent blackmail from the combined Shas-Orthodox block, which might demand huge additional sums for its ghettos, such as higher subsidies for their children (8-10 per family), exemption from work and military service and much more. Also, you would not be located in the middle of your government, but to the left.
To prevent this, you might want to add some centrist spice to the brew. At least three party leaders will line up before your door the day after the election: Shelly, Tzipi and Ya'ir.
Formulating the next government's program should pose no problem. None of the three have said anything that could disturb you. Actually, they have not said much about anything. So take your pick.
WHY NOT take all of them? That would make a National Union (always popular), with only "the Arabs" and Meretz left outside. A coalition of 100 members.
Ah, but there's the rub. Two rubs, actually.
First, in such a coalition, you will be in a minority. You might not be able to turn your every whim into law and zigzag happily along.