Get a priorities list of work you would ideally do, some jobs may not cost as much as you fear and at least you can tell the viewers (ie replacement windows). Do finish anything that is half done or untidy though. It is about saleability as much as extra ££ , no point in holding out for a little more if it takes 6 months longer to sell than your neighbour's, costing extra mortgage payments, council tax commission etc and meanwhile prices rise.
Neutralise - you may not need to change the kitchen or bathroom itself but fresh light paint, less clutter, shiny taps and mirrors and unfussy, clean windows can go a long way.
Kerb appeal - first impressions count so keep lawn and beds neat, path swept and use hanging baskets and containers for colour. Cheap fresh flowers indoors too (Lidl or market ones) , especially on a window sill or table facing into the garden.
Quick hoover , dusting and clearing of surfaces and coffee table (hide under sofa cushions) can give an appearance of order before a viewing. Get some disposable floor wipes to freshen up lino or floor tiles in kitchen and bathroom (dries quickly !).
Try to organise viewings without your children or pets present, less distracting and crowded.
hth