What exactly do you mean by 'beef up'?
The roles of the Bard are (1) Information Provider, (2) Diplomat, (3) Support Fighter, Caster, Scout and Healer.
(1) Access to Gather Information and all Knowledge skills, Bardic Knowledge ability, Greater/Scrying, Clairvoyance and Legend Lore spells (at equivalent or lower levels than other party members)
(2) Diplomacy, Gather Information, Knowledge (Nobility and Royalty), Bluff and Sense Motive as class skills for synergy, Perform (and Bardic Fascinate ability...)
(3a) As a support fighter, a Bard has moderate BAB, can use light armour and shields, and can fight while singing for a significant bonus to self and others. She also has access to good combat spells like haste.
(3b) As a support caster, a Bard has a range of strong offensive Enchantments (like Tasha's, Suggestion, Confusion... generally accessed at lower levels than a Wizard or Sorceror...), some miscellaneous offensive spells (e.g. Grease, Glitterdust, Shout) and good utility/transport spells (Feather Fall, Tongues, Dispel Magic, Dimension Door, Shadow Walk, Plane Shift.)
(3c) As a support scout, a Bard has access to Spot, Listen, Move Silently and Hide as class skills, as well as access to spells that help in the role like invisibility, Sculpt Sound. Admittedly, a Bard with maxed-out stealth/scouting skills will have to forfeit skill points in either social or knowledge areas, but it is a choice that's open to her.
(3d) As a support healer, Bards aren't great but can take one or two Cure spells (and use wands of Cure) in case the Cleric is out of action and a party member (or the Cleric herself!) needs quick healing, and can also at higher levels start using healing items/scrolls via Use Magic Device.
A Bard will generally have two or three of these roles, through ability, skill and spell choices, at which she excels, and will still be able to offer some contribution in other areas. It is unclear to me exactly how the Bard needs 'buffing' - do you think they should fight better (and still have access to information gathering, diplomacy, steath, support caster and support healer abilities)? Do you think they should have more powerful spells (and still cast in light armour, fight competently, and have a large number of skill points to spend on a wide range of class skills?)