Balance is a matter of perception.

First thing set your spending at 100%, next raise taxes until your moral is about 50-60%. Set military spending at 60% and research and social at 20 each. With these settings you should have a positive cash flow at the start.

Use your 5000bc to build a factory on earth and on the first couple of planets you colonize and buy at least the first colony ship. It is also a good idea to build a faster colony ship before your first turn

Get as many planets as you can. Go for the High HQ planets and the planets closest to your rivals first. Back-fill later. With the faster colony ship you should dominate colonization in the early game set on normal or below.

As you acquire more planets build factories (production), markets (money), entertainment (moral), labs (research).

When you have your base empire, you can readjust the economy sliders to something like 35-40 military, 35-40 research and around 25 social. Except for a special needs crunch they can stay at that level through the mid game and/or when you are not at war. Be sure to use the emphasis buttons as needed instaed of messing with the overall economy.

Start building farms, (careful with the farm bonus squares) and embassies on HQ planets. I like to make HQ planets either balanced or financial centers and
Start building Constructor immediately (design a faster one) and grab as many mining resources as possible. The game may ultimately depend on who has the mining resources.

This is my startegy playing at normal as populist party., with diplomacy, social, moral and influence elective bonuses.

Depending on politics and electives there may be other strategies that work better for other players and as you go up in difficulty you will need to be more flexible and take more risks.