I recommend powering up as much as you can as quickly as you can, yeah. STEEM is down right now, so if you're going to invest now wouldn't be the worst time, but you'll need a lot to really make a difference. And your writing skills aren't sucky! If you want to improve, there is a woman involved in the #newbieresteemday initiative in the discord channel who will help out with proofreading.

Voting power decreases with every vote you cast on a scale of 0-100%, with about 1-2% deterioration per vote. People say you should stay above 80%. It takes a day to replenish 20%. You can check where your voting power is ether on steemd.com or on steemstats.com.