This is what I tend to do when playing with fewer players to get more survivable PCs:
Roll stats - 4d6 dropping the lowest, reroll 1s, 6 times places as needed. If you have more than one score with a negative modifier re-roll all 6. Makes for higher stats early, but that means little at higher levels.
Action Points or some other consumable source of bonuses to rolls that represent luck or extra effort. If you are worried about them give them 2 or 3 to start and then award them an extra one for roleplay, criticals, etc. Their are pleanty of rules floating around for various options on this.
Max starting gold.
Backgrounds: choose 3 related skills and make them permanent class skills, get a +1 circumstance bonus in each, choose 1 feat from a limited list of feats. Backgrounds can also include less mechanically obvious details like those menitoned by Danny above.
Sometimes I have also had patrons provide them with a needed item(s) or gp up front to make what they are being hired to do more survivable. Things like a wand of CLW with only 10-20 charges, a MW weapon or two (on loan, the PCs can buy them at the end of the adventure), or some single use items like potions can help a group out when things are tough up front.