You might want to take your bike to a bike shop and ask them the best way to keep the seat up. Plus, they can help determine where the seat should be positioned. A professional bike fit is the optimal choice, but until you start riding more, you probably don't want to invest in that. But you should at least either research yourself about bike fit or ask your LBS for some tips. It can make such a big difference in your riding ability and aches and pains in your body.