A lot of folks are offing advice to enter at various levels of full impulse.
Id like to counter that with my own observations. From my own observations, it seems each ring builds up your speed by a fixed amount. So the tactic i've tried is to creep up to the first ring as slow as your patience allows.
By entering at very slow speeds the first burst of acceleration will only bump up your speed to normal full impulse levels. Essentially making each subsequent speed boost that much more manageable.